Japanese Knife Glossary (A–N) | Terms and Techniques Explained

Japanese Knife Glossary (A-N)

Why Knowing These Words Changes How You Co
Japanese knives are more than tools—they are works of art with a language of their own.
From Yanagiba to Deba, from White Steel to Blue Steel, each word carries centuries of craftsmanship and tradition.
By learning these terms, you’ll not only choose your knives with confidence but also elevate your cooking to a new level of precision, flavor, and artistry.

A

Abrasive grains

Definition: Hard particles used in grinding wheels and whetstones for sharpening and polishing knives.
Details: Synthetic grinding wheels use carborundum (C), green carborundum (GC), or white alumina (WA), each offering distinct hardness and resistance. These factors influence sharpening power and the depth of scratches left on blades. Natural whetstones, made of fossilized plankton (radiolaria), have rounded particles that reduce scratches and provide a smooth finish.
Comparison: Synthetic whetstones sharpen quickly but may leave deeper scratches; natural whetstones cut more gently and yield finer finishes, though quality varies.
Practical Use: Professionals often combine synthetic stones for rough work with natural stones for final finishing. Home cooks benefit from the consistency of synthetic stones, while enthusiasts may enjoy the artisanal results of natural stones.

Aburayaki (Oil Quenching)

Definition: A heat treatment method in which a heated knife is cooled in oil to harden the steel.
Details: Compared to water quenching, oil quenching cools more gradually, producing greater stability and reducing the risk of cracking. The hardened steel retains sharpness and cutting ability, often forming wave-like hamon patterns.
Comparison: Water quenching yields harder and sharper edges but risks cracking; oil quenching is safer and more forgiving, though edges may not hold sharpness as long.
Practical Use: Blacksmiths prefer oil quenching for its stability and higher success rate in production, while water quenching is reserved for high-end knives like honyaki, where maximum sharpness and tradition are emphasized.

Mizuyaki vs Aburayaki

Ago (Chin / Heel of the knife)

Definition: The pointed corner at the bottom end of the blade, closest to the handle. It is commonly referred to as the heel of the knife.
Details: The ago serves as a strong, stable part of the blade, useful for applying extra force when cutting harder materials. In many household knives, it is slightly rounded for safety.
Comparison: Unlike the main cutting edge or tip, the heel is designed for durability rather than fine slicing. Western knives also have a heel, but the term ago is specific to Japanese knives.
Practical Use: The ago is especially useful for tasks such as removing potato eyes, extracting avocado pits, or tackling tougher ingredients that require additional force. Proper use of the heel can improve efficiency and prolong the life of the knife.

Aike

Definition: Small cracks or thread-like holes that appear at the junction where different steels—such as soft iron and hard steel—are joined in a knife.
Details: Most commonly found in awase knives (laminated construction), Aike occurs when adhesion between steels is imperfect or hammering during forging is insufficient. It may resemble tiny worm-like lines or pinholes on the blade surface.
Comparison: In modern quality control, Aike is often regarded as a flaw that reduces visual perfection. However, in traditional craftsmanship, some consider it a natural trace of hand-forging and thus a marker of authenticity, especially when function is not compromised.
Practical Use: Aike generally does not affect cutting performance or durability, but buyers should be aware of it as an aesthetic factor. Professional chefs may overlook minor Aike in favor of blade performance, while collectors may see it as undesirable or, conversely, as proof of hand-forged origin.

Awase (Laminated Construction)

<Honyaki, Awase>

Definition: A type of knife construction in which different metals—typically hard steel and soft iron—are layered together, in contrast to single-steel knives such as honyaki.
Details: In awase knives, the cutting edge is made of high-carbon steel for sharpness, while the outer layers are made of soft iron to provide toughness and ease of sharpening. This structure reduces the risk of breaking, allows easier resharpening, and balances hardness with resilience. The soft iron portion often appears hazy after polishing, giving rise to the name kasumi (misty finish).
Comparison: Compared to honyaki knives (forged from a single piece of steel), awase knives are easier to produce, more forgiving to use, and simpler to sharpen. However, honyaki knives, though more difficult to forge, are regarded as higher-end, offering superior hardness, edge retention, and durability against warping.
Practical Use: Awase knives are the most common type of traditional Japanese kitchen knife, used widely for yanagiba, deba, and other single-bevel styles. They provide an excellent balance for professional chefs—combining performance with ease of maintenance—and are more accessible in price and handling than honyaki.

AUS8

Definition: A mid-grade stainless steel developed by Aichi Steel (Toyota Group), widely used in knives, scissors, and precision tools.
Details: AUS-8 contains 0.70–0.80% carbon, 13–14% chromium, 0.25% molybdenum, and 0.1–0.3% vanadium. This composition provides a balance of hardness (~59 HRC), corrosion resistance, and wear resistance. Compared to lower grades like AUS-6, AUS-8 offers improved durability, while AUS-10 further enhances performance.
Comparison: Compared with high-carbon steels such as Aogami or Shirogami, AUS-8 offers superior rust resistance and ease of maintenance, but may not reach the same extreme sharpness or edge retention. Within the AUS series, AUS-8 is positioned as a versatile middle grade, balancing sharpness, toughness, and affordability.
Practical Use: AUS-8 is valued for its ease of sharpening and balanced performance. It is often used in kitchen knives, folding knives, and medical instruments. For knife users, it provides reliable sharpness with less risk of rusting, making it suitable for both professional and home use.

B

Blade metal

Definition: The material used to forge a knife blade, which determines sharpness, durability, and maintenance needs.
Details: The most common categories are carbon steel, stainless steel, composite steels, and special alloys.
▶Carbon steel: Contains 0.04–2.1% carbon; offers superior sharpness and can be hardened by heat treatment but is prone to rust.
▶Stainless steel: Contains at least 10.5% chromium; highly resistant to corrosion and easy to maintain, though slightly less sharp than carbon steel.
▶Composite steels: Include clad steel (two-layer: hard steel with soft iron, common in traditional Japanese single-bevel knives) and three-layer/warikomi (hard steel core sandwiched by softer layers, typical in Western double-bevel knives).
Special alloys: Such as molybdenum-vanadium steel (for added toughness and wear resistance) and powdered high-speed steel (for maximum hardness and edge retention).
Comparison: Carbon steel excels in sharpness but requires more care; stainless steel prioritizes corrosion resistance and ease of use; composite steels balance hardness with toughness; advanced alloys enhance performance for specialized applications.
Practical Use: Choosing the right blade metal depends on the cooking environment and priorities—professional chefs may prefer carbon or powder steels for sharpness, while home cooks often favor stainless steel for easy maintenance. Composite constructions are widely used in both traditional Japanese and modern Western knives.

Japanese Knife Materials

Blue Steel (Aoko,Aogami)

Definition: A Japanese low-alloy carbon steel originally developed by Hitachi Metals (now Proterial, Ltd.), created by adding chromium and tungsten to Shirogami #2 (White Steel #2). Known for its long-lasting sharpness and toughness, it is a preferred steel for professional kitchen knives.
Details: Aogami is produced in several variations. Aogami #1 has a higher carbon content than Aogami #2, making it harder and offering longer edge retention, though more difficult to sharpen. Aogami #2 is widely used due to its balanced performance, offering excellent sharpness, good resilience, and more approachable sharpening. Both are highly valued for edge stability and reduced chipping compared to Shirogami.
Comparison: Compared to Shirogami (White Steel), Aogami holds its edge longer, resists chipping, and is less prone to wear. However, it is more expensive due to added alloying elements and is harder to sharpen. Shirogami, by contrast, offers extreme sharpness and ease of sharpening but is more brittle and loses sharpness faster.
Practical Use: Aogami #2 is popular among chefs for its balance of sharpness and workability, while Aogami #1 is suited for experts seeking maximum edge retention and hardness. Aogami steels are often chosen for premium Japanese knives, particularly in professional kitchens where durability and cutting precision are required.

Bunka bōchō (Bunka knife)

Definition: A versatile Japanese kitchen knife developed in the late 19th to early 20th century, combining features of both Japanese and Western knives.
Details: The bunka knife has a distinctive sharp, pointed tip, making it suitable for delicate tasks such as decorative vegetable carving, intricate scoring, and precision slicing. Its design reflects the fusion of Western influence with traditional Japanese knife-making during the Meiji to Shōwa period.
Comparison: Often compared with the santoku knife, the bunka shares its role as an all-purpose knife for meat, fish, and vegetables. Some manufacturers use the terms interchangeably, while others differentiate the bunka by emphasizing its pointed tip and slightly different blade geometry.
Practical Use: Popular for home and professional kitchens alike, the bunka knife is valued for versatility and sharpness. Its international recognition as “BUNKA” or “SANTOKU” highlights its reputation as a symbol of Japanese craftsmanship, appealing to chefs worldwide who value precision and delicate techniques.

C

Camellia oil

Definition: A traditional Japanese plant-based oil extracted from the seeds of the camellia tree, widely used for maintaining and protecting knives.
Details: Tsubaki oil prevents rust, provides lubrication, and forms a protective coating on the blade. It is tasteless, odorless, and resistant to drying or solidifying, making it suitable for long-term preservation of high-quality knives.
Comparison: Unlike mineral oils, which may be sticky or leave residues, Tsubaki oil is light, clean, and natural. It has been used for centuries not only on knives but also in Japanese sword care and woodworking tools.
Practical Use: Applied in a thin layer to clean blades after use, Tsubaki oil is trusted by chefs and craftsmen for regular maintenance. While some edible varieties exist, knife-maintenance oil should not be used for cooking purposes.

Carbon

Definition: A fundamental element in steel that determines hardness, sharpness, and durability in knife blades.
Details: In knives, carbon content generally ranges between 0.4% and 1.2%, with most carbon steel knives containing 0.8–1.3%. Carbon is the key factor that allows steel to undergo heat treatment processes such as quenching, enabling superior sharpness and hardness.
Comparison: Higher carbon content provides sharper edges, better edge retention, and improved wear resistance. However, it also makes the steel more brittle, harder to sharpen, and more prone to chipping. Lower carbon steels are easier to sharpen and tougher but lack the extreme sharpness of high-carbon steels.
Practical Use: Carbon steel knives are prized for their exceptional sharpness and are often favored by professionals. However, they are prone to rust and require careful maintenance, including drying after use and oil application. Choosing the right carbon level depends on balancing sharpness, toughness, and ease of care.

Carbon Steel

Definition: A type of steel made primarily from iron and carbon, typically containing 0.04–2.14% carbon. It is one of the two main categories of knife steels, alongside stainless steel.
Details: As carbon content increases, the steel becomes harder and capable of holding a sharper edge. Carbon steel knives usually outperform stainless steel in sharpness and ease of sharpening. However, higher hardness also reduces toughness, making the blade more prone to chipping. Unlike stainless steel, carbon steel rusts easily when exposed to water or food residue and requires diligent care.
Comparison: Carbon steel offers superior cutting performance and easier sharpening compared to stainless steel, but is less resistant to corrosion. Stainless steel, with at least 10.5% chromium, sacrifices some sharpness for ease of maintenance and rust resistance.
Practical Use: Carbon steel knives are favored by professionals and experienced users who can maintain them properly. They require thorough cleaning and drying after each use, and regular application of protective oil. For cooks seeking maximum sharpness and control, carbon steel is a preferred choice despite its maintenance demands.

Casting

Definition: A knife manufacturing method in which metal is melted and poured into molds to form the blade shape.
Details: Casting allows for mass production and the creation of complex designs at relatively low cost. It is a common method in the production of Western-style kitchen knives and contrasts with the traditional Japanese forging method (tatara or hammer forging).
Comparison: Compared to forged knives, cast knives offer consistent quality and higher production efficiency but may lack strength, durability, and sharpness. Forged knives, while more labor-intensive, are generally stronger, longer-lasting, and favored in high-end or traditional Japanese knife-making.
Practical Use: Casting is widely used for affordable household knives that prioritize cost and convenience over maximum performance. Professional-grade and traditional Japanese knives, however, continue to rely on forging to achieve superior cutting performance and durability.

Forged vs Cast

Ceramic knife

Definition: A kitchen knife made from high-hardness ceramic materials, most commonly zirconium oxide, known for its lightness and rust-free properties.
Details: Ceramic knives are about half the weight of steel knives, reducing fatigue during extended use. Their extreme hardness allows them to retain a sharp edge far longer than most metal knives. Because they contain no metal ions, they are immune to rust, prevent food discoloration, and resist odor transfer. They can also be cleaned with bleach or in dishwashers, making them highly hygienic.
Comparison: Compared to steel knives, ceramic knives are sharper for longer and much lighter, but also far more brittle. They cannot handle hard foods or bones and are unsuitable for heavy-duty tasks. Unlike carbon or stainless steel knives, they require special tools for sharpening.
Practical Use: Ceramic knives are popular in households and sometimes in professional kitchens for cutting fruits, vegetables, and boneless meat. However, due to fragility and sharpening limitations, they are best used alongside traditional metal knives rather than as a sole kitchen knife.

Chinese knife

Definition: A broad-bladed kitchen knife widely used in Chinese cuisine, often resembling a hatchet in shape but designed for versatile food preparation.
Details: Typically 18–22 cm in blade length, Chinese cleavers are made from stainless steel or high-carbon steel. They are known for their wide surface area, which provides stability during cutting and serves multiple functions in food preparation. Handles are commonly made of wood or synthetic materials, and proper balance is essential for comfortable use.
Comparison: Unlike Western cleavers, which are often thick and specialized for heavy chopping, the Chinese cleaver comes in three main types—thin, medium, and thick blades—each suited for different culinary tasks. Thin blades are for vegetables and boneless meat, medium blades handle small bones, and thick blades are for heavy-duty bone chopping.
Practical Use: The Chinese cleaver is highly versatile, functioning as a cutting, chopping, crushing, and scraping tool. The flat blade can crush garlic or ginger, the edge slices vegetables and meat, and the blade’s width helps scoop or transfer ingredients. Its multi-functionality makes it indispensable in Chinese kitchens and popular among chefs worldwide.

Chromium

Definition: A chemical element commonly added to knife steels to improve corrosion resistance and durability.
Details: When chromium content reaches 13% or higher, the steel is classified as stainless steel. Chromium contributes not only to rust resistance but also to hardenability, allowing knives to achieve greater hardness and wear resistance.
Comparison: Knives with higher chromium content are easier to maintain and resist rusting, making them more practical for household use. However, compared to high-carbon steels, stainless steels with chromium generally sacrifice some sharpness and edge refinement.
Practical Use: Chromium-rich steels are favored in everyday kitchen knives, where ease of maintenance and resistance to rust are priorities. They are ideal for beginners and home cooks, while professional chefs may prefer lower-chromium carbon steels for maximum sharpness despite the extra maintenance required.

Circular Grindstone

Definition: A rotating disk-shaped sharpening stone, typically used by professional sharpeners to efficiently restore and refine knives.
Details: Mounted above a water tank to remain moist during operation, the circular grindstone prevents overheating that could damage a blade’s temper. Its strong grinding power enables the removal of rust, chip repair, and reshaping of knife geometry.
Comparison: Unlike handheld whetstones used in homes, the circular grindstone allows for continuous, large-scale sharpening with consistent results. However, it requires advanced skill to operate, as improper use may cause uneven grinding or blade damage.
Practical Use: Sharpeners employ the circular grindstone for a three-step process: coarse grinding to remove chips, shape adjustment to restore geometry, and finishing to refine the edge and add luster. Adjusting contact angles allows artisans to create flat surfaces, correct bevels, and smooth imperfections. This tool is indispensable in professional workshops for maintaining high-quality knives.

Cobalt (Co)

Definition: A chemical element added to certain high-grade steels to enhance hardness, wear resistance, and stability in knife blades.
Details: Cobalt strengthens the martensitic structure of steel, prevents carbide dropout, and maintains hardness even at high temperatures. This thermal stability makes it valuable in steels designed for durability and long-lasting sharpness.
Comparison: Compared to steels without cobalt, cobalt alloy steels offer superior edge retention, toughness, and corrosion resistance. They combine hardness with resilience, minimizing brittleness while improving performance under demanding use.
Practical Use: Cobalt alloy steels are often used in premium stainless knives for chefs who require reliable sharpness, toughness, and rust resistance. They are favored in professional kitchens where knives must withstand frequent use without rapid dulling.

Correction whetstone

Definition: A specialized whetstone used to restore and flatten the surface of sharpening stones that have become worn or concave.
Details: Over time, standard whetstones wear down unevenly, leading to concave surfaces that result in inconsistent sharpening. A correction whetstone is rubbed against these surfaces to level them, ensuring a flat and effective sharpening base.
Comparison: Unlike sharpening whetstones, which directly hone knife edges, correction whetstones do not sharpen knives themselves. Instead, they maintain the condition of other whetstones, prolonging their lifespan and improving their performance.
Practical Use: To use, soak the correction whetstone in water and rub it against the uneven whetstone surface until flat. Regular use ensures consistent sharpening results and is highly recommended for both beginners and professionals who rely on whetstones.

Corrosion Resistance

Definition: The ability of knife steel to resist rust and chemical degradation when exposed to moisture, acids, or other corrosive elements.
Details: Corrosion resistance is particularly important in kitchen knives, which are constantly exposed to water, humidity, and food acids. High corrosion resistance improves durability and reduces the need for frequent maintenance, making knives more practical for both home and professional use.
Comparison: Stainless steels, containing at least 13% chromium, are far more resistant to rust than high-carbon steels, though they generally sacrifice a degree of sharpness and edge refinement. Additional alloying elements such as molybdenum and vanadium further enhance corrosion resistance and wear resistance. Powdered steels, like SLD, combine excellent corrosion resistance with superior sharpness, making them a choice material for premium knives.
Practical Use: Knives with strong corrosion resistance are easier to care for but still require proper maintenance. Users should always dry blades thoroughly after use, avoid prolonged exposure to acidic foods or seawater, and store knives in a dry environment. Choosing the appropriate steel based on usage habits and maintenance preferences ensures both performance and longevity.

Japanese Knife Materials 4 Points

D

Damascus Steel

Definition: A type of steel characterized by distinctive wavy surface patterns, created by layering or forging different steels together. Modern Damascus steel imitates the ancient “wootz steel” of India, famed in Europe as Damascus steel, though its original manufacturing process remains partly unknown.
Details: Today’s Damascus knives are typically made by layering high-carbon steel with softer alloys, then folding and forging them repeatedly. This produces beautiful patterns across the blade and improves the steel’s microstructure.
Comparison: Compared to mono-steel blades, Damascus steel offers visual appeal, high hardness, and improved durability through layering. However, performance depends heavily on the quality of the core steel; the outer Damascus layers often serve more for aesthetics and structural support.
Practical Use: Damascus steel is commonly used in Western-style knives as well as some Japanese hybrids. Chefs and collectors value it for its striking patterns, durability, and edge retention. Proper maintenance is still required, as not all Damascus knives are stainless; care varies with the steel composition used in layering.

Danba

Definition:
Danba refers to a blade structure in Japanese knives where the tip is finished with a slightly blunt angle. This feature balances thinness, sharpness, and durability, preventing the tip from chipping easily.
Details:
The design maintains the overall thin profile of the blade while reinforcing the cutting edge at the tip. Depending on the width, Danba may also be described as having Ko-ba (small bevel) or Ito-ba (thread-like bevel), each affecting cutting performance in subtle ways.
Comparison:
Compared to blades with a fully acute tip, Danba knives trade a little sharpness for added strength and durability. This makes them more resilient than extremely thin-edged knives, while still sharper and more precise than Western-style double-beveled blades.
Practical Use:
Danba knives are especially valued for processing fish and meat, where a durable edge is crucial. Proper sharpening involves creating a controlled small bevel with a whetstone, ensuring the edge stays both sharp and stable. With the right maintenance, they deliver long-lasting cutting performance in demanding kitchens.
Cultural Note:
The Danba edge reflects Japanese knife-making’s pursuit of both precision and practicality. By reinforcing the tip, artisans ensure that knives remain reliable for chefs who handle delicate yet intensive work, such as filleting fish in traditional cuisine.

Deba

Definition: A traditional Japanese kitchen knife with a thick, heavy blade, primarily designed for filleting and butchering fish.
Details: Deba knives typically range from 10 cm to 50 cm in blade length, with 15–20 cm being most common. They usually feature a single-bevel edge, though some regional variations use a double bevel. The spine is thick and angled near the handle, allowing leverage to cut through fish heads and bones.
Comparison: Unlike thinner Japanese knives such as yanagiba or usuba, the deba is built for strength and durability. It can cut through fish bones and tougher ingredients without damaging the blade, though it is not designed for fine slicing or delicate work.
Practical Use: The deba excels at filleting fish, removing heads, and breaking down whole fish. It can also be used for poultry or meat, but its primary role remains in seafood preparation. Chefs and home cooks alike value it as an essential tool for handling fish of various sizes.
History: Originating in the Edo period, the deba is mentioned in texts such as the Sakai Kanjin. Its name is believed to derive from a blacksmith nicknamed “Deppa” (“protruding tooth”), whose work popularized this knife style. Over time, the name evolved into “Deba.”

Dimple Processing

Definition: A knife blade treatment in which small indentations (dimples) are pressed or ground into the blade surface to reduce food adhesion.
Details: The dimples decrease the contact area between the blade and ingredients, preventing food from sticking. This enhances smooth cutting and makes it easier to handle sticky foods such as potatoes, pumpkins, or squash. In addition to functionality, dimples add a distinctive visual appeal to the knife.
Comparison: Unlike plain blades, which often cause food to cling during slicing, dimple-processed blades allow ingredients to glide more easily. While similar to granton edges in Western knives, Japanese dimple processing tends to be more subtle in depth and spacing.
Practical Use: Dimple processing is especially effective for chefs who need efficient, uninterrupted cuts in a professional kitchen. It improves workflow and reduces effort when handling large volumes of food. Home cooks also benefit from the added ease of use and reduced frustration with sticky ingredients.
Applications: Commonly used in santoku, gyuto, and other multi-purpose knives, dimple processing is valued for combining functionality with design, improving both performance and appearance.

Double-edged blade (Ryōba)

Definition: A knife edge structure where both sides of the blade are symmetrically sharpened, unlike single-edged blades which are ground only on one side.
Details: Double-edged blades are most common in Western-style kitchen knives. Because the bevels are symmetrical, the knife can cut straight through food without requiring adjustment. This design also makes the knife equally usable for both right-handed and left-handed users.
Comparison: Compared to single-edged Japanese knives, double-edged blades are generally less sharp and precise but offer greater versatility and ease of use. Single-edged knives excel at creating clean, smooth cuts (e.g., sashimi) and are thinner at the edge, while double-edged blades are more robust and user-friendly for everyday cooking.
Practical Use: Double-edged blades are widely used in household and professional kitchens for general cutting tasks, including chopping, slicing, and dicing. Their balanced structure makes them particularly well-suited for Western knife styles such as the gyuto (Japanese chef’s knife influenced by Western design) and santoku.
Cultural Note: While Japanese traditional knives are often single-edged to enable precise cuts and separation of ingredients, the influence of Western cooking led to the widespread adoption of double-edged blades in Japan, especially for multipurpose knives.

Single vs. Double-Edge Knives

E

Ebony (Kokutan)

Definition: A premium knife handle material made from ebony wood, valued for its hardness, durability, and luxurious appearance.
Details: Ebony is extremely dense and resistant to water and oil, making it ideal for demanding kitchen environments. Its deep black color and natural luster provide a sense of refinement and exclusivity. Due to its rarity, knives with ebony handles are often considered high-end.
Comparison: Compared to magnolia (ho) or rosewood (shitan) handles, ebony is significantly harder and more durable, though more prone to cracking if exposed to rapid temperature changes. While magnolia emphasizes lightness and grip comfort, ebony emphasizes strength and elegance.
Practical Use: Ebony handles provide excellent ergonomic comfort, allowing prolonged use without fatigue. They are especially favored by chefs and collectors seeking a combination of performance and beauty. Proper care, such as avoiding extreme temperature shifts, helps maintain their longevity.
Cultural Note: Ebony (kokutan) has long been prized in Japan not only for tools and utensils but also for fine crafts and instruments, symbolizing luxury and craftsmanship. Its use in knife handles reflects both practicality and cultural heritage.

Type of Handle

Related websites
Japanese Knife Handles Guide | KIREAJI

Etsuke (Handle Mounting)

Definition: The process of attaching a handle to a knife blade, ensuring structural stability, proper balance, and comfortable usability.
Details: The handle is the part of the knife gripped by the user, and its attachment greatly influences control and safety. Common handle shapes include oval (often used for deba) and chestnut-shaped (oval with a flat side), which prevent slipping during use.
Comparison: High-end Japanese knives often feature natural wood handles such as magnolia, ebony, rosewood, or zelkova, emphasizing durability and aesthetics. More affordable knives may use plastic handles, which are lightweight and water-resistant but lack the traditional feel and elegance of wood.
Practical Use: The attachment process involves heating or preparing the tang (nakago), inserting it carefully into the handle, and securing it with gentle hammering. Proper fitting avoids gaps, instability, or cracks. Afterward, the handle is polished for a finished look. A well-fitted handle ensures comfort, precision, and durability in daily use.
Cultural Note: Etsuke is a traditional skill in Japanese knife-making that highlights the harmony between blade and handle. Craftsmen often select wood materials not only for function but also for aesthetic and cultural value, reflecting Japan’s heritage of tool-making.

F

Finishing whetstone

Definition: A type of sharpening stone with a grit level of 5000 or higher, used in the final stage of knife sharpening to refine the edge and polish the blade surface.
Details: Finishing whetstones smooth the blade edge, producing a razor-sharp finish and reducing damage to ingredients during cutting. They also create a polished surface that enhances the presentation of sliced foods. High-quality finishing stones are durable and maintain consistent performance when properly cared for.
Comparison: Unlike coarse or medium-grit stones that repair chips or shape the edge, finishing whetstones are specialized for honing and polishing. Natural stones provide unique textures and finishes but can be expensive, while synthetic stones ensure uniform grit and ease of use.
Practical Use: Typically used after coarse and medium stones, finishing whetstones are essential for knives such as yanagiba, kiritsuke, and deba, where precision and presentation matter. Grit levels around 5000–6000 are recommended for meat knives, while levels up to 8000 suit vegetable or fruit knives for smooth, refined cuts.
Maintenance: To maintain their effectiveness, finishing whetstones require regular flattening with a lapping or correction stone. Uneven surfaces reduce sharpening quality, so consistent care ensures optimal results.

Type of Whetstone

Forging (Hizukuri)

Definition: A knife-making process in which steel is heated to high temperatures (typically above 1,000 °C) and shaped by hammering or pressing, improving both form and internal structure.
Details: Forging refines the crystalline structure of the steel, making it stronger, tougher, and more uniform. The heated material is softened for shaping, then repeatedly struck or pressed until it takes the desired blade form. Traditional Japanese knife-making often combines forging (hizukuri) with forge welding (wakashi-tsuke).
Comparison: Unlike forge welding, which bonds different metals together, forging primarily shapes a single piece of steel. Compared to stamped knives (cut from sheet steel), forged knives are stronger, more durable, and offer superior cutting performance.
Practical Use: In production, raw steel is cut to size, heated to red-hot, then forged with hammers or mechanical presses. After shaping, the blade undergoes cooling, grinding, and polishing before hardening and sharpening. This process produces knives that resist deformation and retain sharpness over time.
Cultural Note: In Japan, forging (hizukuri) is regarded as a cornerstone of traditional craftsmanship. Passed down for centuries, it embodies the philosophy of transforming raw steel into a functional yet refined tool, symbolizing both strength and artistry.

Forging (Hizukuri)

Friction Resistance

Definition: The cutting resistance a knife encounters when passing through food, caused by friction between the blade surface and the ingredient.
Details: Friction resistance directly influences sharpness and ease of cutting. It depends on several elements including blade angle, thickness, grind shape, and surface finish. For example, polished or convex blades often reduce friction, while thicker or steeper edges increase resistance.
Comparison: Knives with a narrow blade angle and thin cross-section experience less friction, making them ideal for precision tasks like sashimi slicing. Conversely, thicker blades with wider angles provide durability but generate more resistance, making them better suited for tough ingredients.
Practical Use: Optimal blade thickness near the edge—around 0.45 to 0.55 mm at ~3 mm from the edge—maintains balance between sharpness and durability. Adjusting the grind and finish can tailor performance for different foods, from delicate vegetables to dense meats.
Cultural Note: In Japanese craftsmanship, minimizing friction resistance is closely tied to achieving “smooth, beautiful cuts” (kireaji). This reflects the philosophy that a knife should not only cut efficiently but also preserve the integrity and presentation of ingredients.

Materials 4 points

G

Garasaki (Butchery knife)

Definition: A traditional Japanese knife designed for processing meat and fish, particularly suited for breaking down poultry and cutting through bones.
Details: Garasaki knives are characterized by their thick, durable blades, typically ranging from 180 mm to 270 mm in length. The shorter 180 mm size is especially popular due to its balance between strength and ease of handling. Crafted from steels such as Yasuki steel or high-carbon steel, they deliver both long-lasting sharpness and cutting power.
Comparison: Compared to deba knives, which are also used for fish processing, garasaki knives are heavier and more robust, making them better suited for cutting through tougher bones, such as those in chicken. While deba excels in filleting precision, garasaki provides strength for butchery tasks.
Practical Use: Ideal for breaking down chicken, fish, and other meats, garasaki knives are commonly used in both professional kitchens and home cooking. Their versatility makes them valuable tools for chefs who need durability and efficiency.
Cultural Note: Traditionally forged using Japanese hammering and heat-treatment methods, garasaki knives embody the blend of functionality and craftsmanship found in Japanese cutlery. They stand as a symbol of practical strength and cultural heritage in Japanese cooking.

Ginsan (Silver steel)

Definition: A stainless alloy steel commonly used in Japanese knives, valued for its balance of sharpness, corrosion resistance, and ease of sharpening.
Details: Ginsan is primarily composed of carbon and chromium, giving it stainless properties while retaining high hardness. Its dense microstructure allows for a finely honed edge with excellent sharpness. Despite being stainless, it maintains qualities closer to carbon steel in cutting feel and sharpening responsiveness.
Comparison: Unlike high-alloy stainless steels that are harder to sharpen, Ginsan offers ease of maintenance while still providing superior cutting performance. Compared to carbon steels, it is far less prone to rust, making it more beginner-friendly.
Practical Use: Ginsan knives excel in precision cutting tasks such as slicing meat, fish, and vegetables. Their sharpness and stability make them suitable for both professional chefs and home cooks. Sharpening can be done easily with standard whetstones, making upkeep accessible even for less experienced users.
Cultural Note: Known in Japanese as Ginsanko (銀三鋼), Ginsan was developed as a stainless alternative that preserves the traditional cutting performance of Japanese knives. It reflects the Japanese pursuit of combining modern materials with classic knife-making traditions.

Grinding wheel for surface repair

Definition: A specialized abrasive tool used to restore knife blades by removing chips, correcting deformations, and smoothing surfaces.
Details: Typically made of alumina or diamond abrasives, grinding wheels have strong cutting power and are available in different grain sizes and shapes. Coarse wheels are used for major repairs, while fine wheels are reserved for finishing and fine adjustments.
Comparison: Compared to whetstones, grinding wheels are faster and more aggressive, making them suitable for significant damage or reshaping tasks. However, whetstones allow for more precise manual control, making them better suited for routine sharpening and delicate finishing.
Practical Use: Grinding wheels are mounted on machines and rotated at high speed. They are used to remove chips, restore edge angles, or smooth blade surfaces. Diamond wheels are especially effective for hard steels, while alumina wheels are versatile for general knife maintenance. Proper selection of diameter and thickness ensures efficiency and accuracy.
Cultural Note: While traditional Japanese craftsmen often rely on waterstones (toishi) for fine sharpening, grinding wheels are commonly used in workshops for heavy repair work and initial shaping. They complement, rather than replace, hand-sharpening traditions in Japanese knife-making.

Gyuto (Chef’s knife)

Definition: A versatile Japanese kitchen knife inspired by Western chef’s knives, designed for cutting meat, fish, and vegetables with precision.
Details: The gyuto features a long, narrow blade with a pointed tip and a slight curvature in the middle, enabling both push and pull cuts. Blade lengths generally range from 180 mm to 300 mm, with professionals often preferring 240 mm or longer, while home cooks typically choose around 200 mm.
Comparison: Unlike the santoku, which has a broader and more stable blade, the gyuto’s narrower blade reduces resistance, making it more efficient for slicing meat and fish. It offers superior precision, especially for tasks like trimming sinew or thinly slicing sashimi. Compared to the deba, the gyuto is lighter and better suited for versatility rather than heavy-duty fish butchery.
Practical Use: With its pointed tip and curved edge, the gyuto excels at slicing meat, filleting fish, and cutting large vegetables such as cabbage or pumpkin. Its adaptability makes it a favorite in both professional kitchens and home cooking.
Cultural Note: Although Western in origin, the gyuto has been fully integrated into Japanese culinary culture. It represents the adaptability of Japanese craftsmanship, blending Western design with traditional steelwork to create a knife that suits both Japanese and global cooking styles.

H

Hamaguriba (Clam blade)

Definition: A traditional Japanese knife edge geometry where the cross-section of the blade resembles the rounded shape of a clam shell.
Details: The edge of the blade is slightly curved, reducing the surface area that contacts food. This design is particularly common in high-quality Japanese knives, where precise cutting performance is essential.
Comparison: Unlike flat bevel edges, the hamaguriba reduces friction and allows smoother, more efficient cuts. It provides greater sharpness and control, but requires more skill to sharpen correctly in order to preserve its unique geometry.
Practical Use: Commonly found in yanagiba, usuba, and other traditional Japanese knives, the hamaguriba excels in cutting fish and vegetables with minimal resistance. For chefs, maintaining this geometry during sharpening is key to sustaining both performance and longevity of the blade.

Hammer

Definition: A fundamental tool in knife-making, used to strike heated steel during forging and welding processes.
Details: Hammers come in various weights and shapes tailored to specific tasks in blacksmithing. In knife manufacturing, heavy hammers are typically used to reshape red-hot steel, refine its crystalline structure, and ensure uniform density. Specialized hammers may also be used for fine adjustments or surface finishing.
Comparison: Unlike modern mechanical presses that apply consistent pressure, hand-hammering provides nuanced control over shape and structure. Mechanical tools allow efficiency and uniformity, but hand-hammering remains central to traditional Japanese craftsmanship, where subtle differences affect final blade performance.
Practical Use: During forging (hizukuri), hammers are used to elongate, thin, and shape the blade. In forge welding (wakashi-tsuke), they bond layers of different steels under heat and pressure. Repeated hammering improves toughness and contributes to lasting sharpness in the finished knife.
Cultural Note: Hammering (tsuchi-uchi) symbolizes the spirit of Japanese blacksmithing, passed down for centuries. The rhythmic sound of hammer on steel reflects the craftsman’s skill, patience, and pursuit of perfection, forming the foundation of traditional knife-making.

Hammered Finish

Definition: A finishing technique in which the blade surface is intentionally hammered to create textured indentations, combining visual appeal with functional performance.
Details: After forging, the blade is hammered to form small dimples on its surface. These indentations reduce food adhesion and also enhance the blade’s structural stability. The hammered surface creates a unique pattern, giving each knife an individual, handcrafted look.
Comparison: Unlike mirror-polished blades, which emphasize smooth aesthetics, hammered finishes focus on both beauty and practicality. Compared to plain satin finishes, tsuchime provides better food release and a stronger artisanal impression.
Practical Use: The hammered texture reduces the contact area between blade and food, preventing ingredients from sticking. This improves efficiency when slicing meat, fish, or vegetables. The surface also helps reduce overall friction, aiding in smoother cutting and prolonging edge sharpness.
Cultural Note: Known in Japanese as tsuchime, this finish highlights the blacksmith’s handwork and individuality. Each hammer mark reflects the artisan’s skill, making tsuchime knives both a tool and a piece of functional art cherished in Japanese knife-making tradition.

Hamoto (Heel)

Definition: The base of the blade near the handle, opposite the tip, designed for tasks that require extra strength, pressure, or precision.
Details: The hamoto is typically thicker and more obtusely angled than other parts of the blade, providing robustness for demanding work. In heavy-duty knives such as deba-bōchō, the hamoto is especially reinforced to handle cutting through bones or dense ingredients.
Comparison: Compared to the hasaki (tip), which is used for delicate precision cuts, the hamoto is specialized for forceful tasks. Western knives often integrate the heel into the bolster, while Japanese knives leave the hamoto more exposed for direct, powerful cutting.
Practical Use: The hamoto is ideal for peeling thick-skinned vegetables, chopping dense ingredients, or cutting through small bones and tendons. Its proximity to the handle gives the user better leverage and control, making it suitable for trimming, prepping, and precision cutting.
Cultural Note: In Japanese knives, hamoto symbolizes the knife’s strength and endurance. Especially in deba knives, it reflects the tradition of designing blades for both delicate filleting and heavy-duty butchery, embodying the duality of Japanese culinary craftsmanship.

Handle

Definition: The part of the knife gripped by the user, directly influencing comfort, balance, and control. Handle design and material selection greatly affect both usability and durability.
Details: In Japanese-style (wa) handles, the tang (nakago) is inserted into the handle and secured, allowing for easy replacement. Commonly, a ferrule made of buffalo horn reinforces the junction. Western-style handles (yo) are constructed by sandwiching the tang between scales (wood or resin) and fixing them with rivets, creating a more permanent but less replaceable design.
Comparison: Wa handles are lighter and provide better balance toward the blade, favored in traditional Japanese cutlery. Yo handles are heavier, often ergonomically contoured, and offer a solid grip, popular in Western kitchens. While wa handles can be replaced individually, yo handles generally require replacement of the entire knife if damaged.
Practical Use: Handle materials vary by purpose—magnolia wood offers lightness and grip for professional use, ebony provides durability and luxury, rosewood and zelkova offer aesthetic richness, while resin or laminated plywood improve water resistance for heavy kitchen use. Proper maintenance prevents cracking or loosening.
Cultural Note: Known in Japanese as e, the handle reflects regional traditions and preferences. From simple magnolia handles in Sakai knives to ornate ebony with buffalo horn ferrules, the handle is not just functional but also an expression of Japanese craftsmanship, balancing tradition with modern practicality.

Type of Handle

Hardness

Definition: A key property of knife steel that determines resistance to deformation and wear, directly affecting sharpness, edge retention, and durability.
Details: Knife hardness is most commonly measured using the Rockwell Hardness Scale (HRC). Standard kitchen knives typically fall between HRC 50–65. Higher values indicate stronger edge retention but can also increase brittleness, while lower values improve toughness but reduce sharpness longevity. Alternative methods such as Vickers or Knoop hardness tests exist but are rarely used in knife-making.
Comparison: Harder steels (e.g., HRC 62–65 in honyaki or powdered steels) retain edges longer but are more difficult to sharpen and prone to chipping. Softer steels (HRC 50–55) sharpen easily and resist chipping but dull quickly. Balanced steels (HRC 58–61, common in many Japanese knives) offer a middle ground suitable for both professionals and home cooks.
Practical Use: Selecting the right hardness depends on intended use. Professional sushi chefs often prefer harder blades for razor-sharp precision, while home cooks may favor slightly softer steels for ease of sharpening and durability. Maintenance practices, such as proper sharpening angle and avoiding hard materials, are essential regardless of hardness.
Cultural Note: In Japanese craftsmanship, kōdo is not only a technical metric but also a reflection of philosophy—balancing extreme sharpness with practical usability. The pursuit of the ideal hardness exemplifies the Japanese approach of harmony between performance and longevity in knife-making.

Japanese Knife Materials 4 points

Hasaki (Edge / Tip)

Definition: The cutting edge or tip of the knife, located at the foremost part of the blade, which makes direct contact with food during cutting.
Details: The hasaki is sharp and finely pointed, enabling precision work. Its exact shape varies depending on the type of knife—for instance, yanagiba knives feature a long, narrow tip for slicing sashimi, while gyuto knives have a more curved tip for versatility.
Comparison: Compared to the broader cutting edge of the blade body, the hasaki is specialized for delicate, detail-oriented tasks. A dull or damaged tip greatly reduces a knife’s overall effectiveness, even if the rest of the edge is sharp.
Practical Use: The hasaki is used for fine tasks such as scoring ingredients, trimming tendons, peeling fish skin, or making decorative garnishes. In sushi and sashimi preparation, its precision determines the quality of each slice.
Maintenance: Since the hasaki plays a critical role in cutting performance, it requires consistent sharpening and careful handling. Proper maintenance of the tip preserves both sharpness and accuracy, ensuring optimal results in cooking.

Hasen (Blade line)

Definition: The line formed by the cutting edge of a knife, which determines its overall shape and cutting characteristics.
Details: The blade line may be straight or curved, and its geometry directly affects performance. A straight blade line provides stability for chopping, while a gently curved line enhances slicing motion. For sashimi knives (yanagiba), the curve toward the tip—known as sori—is especially important for clean pulling cuts.
Comparison: In Western knives, the blade line is often designed for rocking motions (e.g., chef’s knives), whereas Japanese knives emphasize pulling cuts with longer, flatter blade lines. Irregularities in the blade line are considered defects that reduce performance and value.
Practical Use: A well-maintained blade line ensures sharpness, control, and efficiency. Proper sharpening must preserve the intended geometry, taking into account the entire bevel from the shinogi line. For professionals, a precise blade line is essential for both functionality and quality assessment.

Hawatari (Blade length)

Definition: The measurement of the knife’s cutting edge, typically from heel to tip. For knives with a bolster, it is measured from the bolster to the tip.
Details: The method of measurement varies by knife type. Deba and double-edged household knives are measured by the full cutting edge, while sashimi knives (yanagiba) are measured from the bolster to the tip. Blade length directly affects cutting efficiency, control, and suitability for different tasks.
Comparison: Household knives usually range from 150 mm to 210 mm. Petty knives are about 150 mm, santoku about 170 mm, and larger gyuto around 210 mm. Yanagiba knives, however, are significantly longer: 240 mm for home use, 270 mm for intermediate skill or smaller kitchens, and 300 mm for professional chefs.
Practical Use: Choosing the correct blade length depends on kitchen size, cutting board dimensions, and typical ingredients. Shorter blades are nimble for precise work, while longer blades provide cleaner cuts for large fish or meat. Matching blade length to the user’s environment ensures optimal performance and comfort.

Heat Treatment

Definition: A controlled thermal process applied to steel during knife manufacturing to optimize hardness, toughness, and durability, ensuring superior cutting performance.
Details: Heat treatment consists of multiple stages, including annealing (stress relief and softening), quenching (hardening through rapid cooling), tempering (adding toughness and flexibility), and sometimes cryogenic treatment (sub-zero cooling to complete martensitic transformation). Each step refines the steel’s crystalline structure, directly influencing sharpness and edge retention.
Comparison: Compared to untreated steel, properly heat-treated blades maintain sharper edges longer and resist deformation. Japanese knives often emphasize meticulous quenching and tempering to balance extreme sharpness with practical toughness, whereas mass-produced knives may use simpler or standardized heat cycles.
Practical Use: Heat treatment allows blades to achieve a hardness range of approximately HRC 58–65, ideal for high-performance knives. Different quenching mediums (water, oil, or air) and precise tempering cycles adjust a knife’s balance of sharpness, durability, and ease of sharpening. Cryogenic treatment further enhances wear resistance in high-carbon steels.
Cultural Note: In Japanese craftsmanship, netsushori is regarded as the “soul” of the knife. Each blacksmith develops proprietary techniques, often passed down through generations, to create unique cutting characteristics. This attention to detail reflects the philosophy of harmony between sharpness, resilience, and artistry.

Hira (Flat)

Definition: The flat section of a Japanese knife blade, located between the ridge line (shinogi) and the cutting edge (kiriha).
Details: The hira is typically smooth and even, forming the central portion of the blade’s geometry. It not only contributes to the knife’s structural integrity but also influences how smoothly the blade passes through ingredients.
Comparison: Compared to the kiriha (cutting bevel), which directly forms the edge, the hira is broader and flat. While it does not cut directly, its flatness helps guide the blade and supports stable cutting performance.
Practical Use: The hira can be used for light crushing of ingredients such as garlic or ginger. It also aids in precision cutting when working in tandem with the cutting edge or tip. Its role is particularly important in single-bevel Japanese knives like yanagiba or usuba, where blade geometry strongly affects performance.
Related Parts: The shinogi (ridge line) separates the hira from the edge bevel, reducing resistance during slicing. The kissaki (tip) extends from the hira to allow for detailed, delicate cutting tasks.

Honbazuke

Definition: A specialized hand-sharpening process applied to new knives or after major maintenance, designed to maximize sharpness, stability, and long-term cutting performance.
Details: Honbazuke involves refining the blade to an even sharper angle than its factory edge, often finished with natural or high-grit synthetic whetstones. A micro-bevel (itoba) is typically added to stabilize the edge and reduce chipping. While machines can perform initial sharpening, honbazuke by skilled craftsmen achieves superior precision and longevity.
Comparison: Unlike standard machine sharpening, which provides a usable but generic edge, honbazuke creates a highly refined, razor-sharp edge customized to the blade geometry. For single-bevel knives, it emphasizes flat polishing along the main bevel. For double-bevel knives, it can focus either on the edge line or on flattening the full bevel (beta-togi) for easier future maintenance.
Practical Use: A knife treated with honbazuke is ready for immediate professional use, cutting through ingredients with minimal resistance. The process not only ensures exceptional sharpness but also simplifies resharpening, as the geometry is aligned for easier upkeep.
Cultural Note: Honbazuke, literally meaning “true multiple sharpening,” is deeply rooted in Japanese knife-making tradition. It represents the craftsman’s final touch, where skill and sensitivity elevate the knife from a tool into a precision instrument, embodying both functional excellence and artisanal pride.

Honyaki (Single-steel construction)

Definition: A type of Japanese kitchen knife forged from a single piece of steel, without lamination. Unlike awase knives that combine hard steel with soft iron, honyaki blades achieve both hardness and resilience within one material.
Details: During the heat treatment process, blacksmiths apply differential heating and quenching, creating regions of varying hardness within the blade. This technique mirrors the method used in Japanese sword-making, where hard and soft areas coexist to balance cutting performance with durability.
Comparison: Honyaki knives are considered the highest tier of Japanese knives, requiring advanced skill and effort to produce. Compared to awase knives, they are harder, more wear-resistant, and less prone to warping even after long-term use. However, they are also more difficult to sharpen and more fragile if handled improperly. Awase knives, by contrast, are easier to sharpen and more forgiving, making them widely used in professional kitchens.
Practical Use: Popular among sushi and sashimi chefs, honyaki knives provide unmatched sharpness and edge retention, making them ideal for tasks requiring precision and aesthetic perfection, such as slicing sashimi. Because of their brittleness, they demand careful handling and skilled maintenance.
Cultural Note: The name honyaki literally means “true-forged,” reflecting its roots in Japanese swordsmithing. A honyaki knife is seen not only as a culinary tool but also as a work of art, representing mastery of traditional forging techniques and carrying the prestige of Japanese craftsmanship.

HRC (Rockwell hardness)

Definition: HRC is a scale of the Rockwell Hardness Test, specifically used to measure the hardness of metals like knife steel. It is determined by applying a set pressure with a diamond cone and measuring the steel’s resistance to deformation.
Details: Knife hardness typically ranges between HRC 55–67. Higher values mean harder steel with superior edge retention, but also greater brittleness. Lower values provide toughness and ease of sharpening but require more frequent maintenance.
Comparison: Stainless steel kitchen knives usually fall around HRC 56–58, balancing durability and maintenance ease. Premium Japanese steels such as aogami (Blue Steel) or shirogami (White Steel) often reach HRC 62–64, achieving extreme sharpness. Powdered high-speed steels may exceed HRC 65, offering unmatched wear resistance but requiring careful handling.
Practical Use: A higher HRC allows for precise, effortless slicing with long-lasting sharpness, ideal for professional chefs. However, extremely hard knives are prone to chipping and can be difficult to sharpen. Home cooks often benefit from knives in the mid-range (HRC 58–61), balancing edge retention with manageable upkeep.
Cultural Note: In Japanese craftsmanship, HRC values are not merely technical measurements but markers of a blade’s character. Each blacksmith fine-tunes heat treatment to achieve an optimal hardness, reflecting both tradition and philosophy—whether prioritizing ultimate sharpness or practical resilience.

I

Itoba (Thread Blade)

Definition:
Itoba (糸刃) refers to an extremely fine secondary bevel applied at the tip or edge of a knife to enhance its sharpness and cutting precision.
Details:
The Itoba is created by sharpening the edge at a much smaller angle than the main cutting bevel. This results in a thinner, sharper line that penetrates food with minimal resistance. Achieving it requires precise sharpening skills, often on fine-grit whetstones.
Comparison:
Compared to a standard single bevel, Itoba creates a finer edge that excels in precision but requires more delicate maintenance. Without proper care, its thin edge may wear faster than a regular bevel, making it a choice favored by professionals who value sharpness over ease of upkeep.
Practical Use:
Itoba is particularly important for sashimi knives and fine slicers, where smooth, clean cuts determine both the visual presentation and texture of the dish. Chefs often maintain the Itoba carefully to ensure the highest level of sharpness during service.
Cultural Note:
The Itoba edge reflects the Japanese pursuit of precision in cuisine, especially in sushi and kaiseki traditions where the beauty of the cut is as important as taste. Master sharpeners pass down the skill of creating and maintaining Itoba as part of Japan’s culinary heritage.

J

Japanese knife (Wabōchō)

Definition: A traditional Japanese kitchen knife that evolved from Japan’s unique culture and craftsmanship, designed to meet the precise demands of Japanese cuisine.
Details: Most wabōchō are single-beveled, sharpened only on one side, which enables ultra-thin slicing with minimal damage to the structure of ingredients. They are typically forged from high-carbon steel or stainless steel, combining sharpness with durability.
Comparison: Unlike Western knives, which are generally double-beveled and optimized for versatility, wabōchō prioritize precision and purity of cut. For example, yanagiba excels at sashimi slicing, while usuba is dedicated to vegetables. Western knives often prioritize ease of maintenance, while wabōchō demand more care but reward with superior cutting performance.
Practical Use: Common types include the deba (for filleting fish and cutting through bones), yanagiba (for sashimi and sushi slicing), and usuba (for precise vegetable cutting). Each knife is tailored for specific tasks, ensuring professional-level results in traditional Japanese cuisine.
Cultural Note: Wabōchō embody centuries of artisanal knowledge, reflecting the philosophy of harmony between food and craftsmanship. Beyond functionality, they are works of art, admired for their aesthetics, replaceable handles, and the deep cultural heritage they carry from the world of Japanese swordsmithing into the kitchen.

Jigane (Soft-iron cladding)

Definition: Jigane refers to the softer iron or mild steel used as the base material in many traditional Japanese knives. It forms the body of the blade, supporting the harder cutting edge (hagane).
Details: In awase construction, jigane is forge-welded with hagane to create a composite blade. While the hard steel ensures sharpness and edge retention, the jigane provides flexibility and ease of maintenance. This balance between soft and hard materials is a hallmark of Japanese knife-making.
Comparison: Western knives are usually made from monosteel or three-layer stainless cladding. By contrast, traditional Japanese knives often feature jigane, which reduces weight and adds resilience. A honyaki knife, made from a single piece of steel, omits jigane entirely, making it harder but more brittle.
Practical Use: Jigane makes sharpening easier, as the softer material grinds down more readily than hard steel. It also absorbs impact, reducing the risk of chipping during tasks such as filleting or vegetable preparation. Professional chefs benefit from this balance, as knives remain sharp yet relatively easy to maintain.
Cultural Note: In high-end knives, jigane often displays kasumi (hazy) or wave-like patterns, which are not only functional but also aesthetic signatures of the blacksmith’s craft. The contrast between jigane and hagane symbolizes the duality of Japanese blades—strength paired with subtlety.

K

Kamausuba (Sickle-shaped usuba)

Definition: A specialized variation of the usuba knife, the kamausuba features a curved spine and pointed tip, making it ideal for delicate vegetable work in traditional Japanese cuisine.
Details: Typically forged with a very thin blade (180–210 mm), the kamausuba minimizes damage to vegetable fibers, preserving flavor and texture. Its unique sickle-like shape enables both precision peeling and controlled slicing.
Comparison: Unlike the kanto usuba (square-tip usuba), the kamausuba is characterized by its pointed tip, which allows for intricate decorative cutting and peeling. While the kanto style excels at straight slicing, the kamausuba provides greater versatility in precision tasks.
Practical Use: Perfect for techniques such as katsuramuki (rotary peeling of daikon), fine vegetable slicing, and decorative garnishes. Professionals often prefer the longer 210 mm size for versatility, while the 180 mm size suits smaller kitchens or detailed work.
Cultural Note: The kamausuba is closely associated with Sakai City, a historic center of Japanese knife-making. It embodies the refinement of Japanese culinary traditions, where aesthetics and precision in vegetable preparation are regarded as essential elements of cuisine.

Kanadoko (Anvil)

Definition: The kanadoko is the anvil used in traditional Japanese knife-making. It provides the solid base on which heated steel is hammered, shaped, and refined during forging.
Details: Typically made of iron or steel, the kanadoko is designed to withstand repeated impact and high temperatures. While its primary surface is flat for general forging, specialized kanadoko may include concave or grooved areas to aid in forming distinctive features such as the ura-suki (hollow grind on the backside of Japanese knives).
Comparison: In Western blacksmithing, anvils are often larger and more standardized. By contrast, Japanese kanadoko are frequently custom-shaped for specific tasks, reflecting the artisanal precision of wa-bōchō production. This specialization allows for fine adjustments unique to Japanese blades.
Practical Use: Used for shaping heated steel into the basic blade form, straightening warps after heat treatment, and forming the ura-suki. The anvil is indispensable for producing knives that balance durability, sharpness, and aesthetic refinement.
Cultural Note: The kanadoko embodies centuries-old forging traditions. Its presence in the workshop represents the continuity of Japanese craftsmanship, where subtle variations in surface design mirror the individuality of each artisan. More than just a tool, it is a cornerstone of the quality and cultural identity of Japanese knives.

Kasumi

Definition: Kasumi refers to a type of Japanese knife made by laminating soft iron (jigane) with hard steel (hagane). The name “kasumi,” meaning “mist,” comes from the hazy, cloud-like appearance that develops where these two metals meet along the blade.
Details: The jigane provides flexibility and ease of sharpening, while the hagane ensures superior sharpness and cutting performance. This structure balances durability with functionality, making kasumi knives reliable for a wide range of culinary tasks.
Comparison: Unlike honyaki knives, which are forged from a single piece of steel and prized for their hardness and difficulty of production, kasumi knives are more approachable. They are easier to sharpen and maintain, though generally less expensive and slightly less durable than honyaki.
Practical Use: Kasumi knives are versatile and suitable for meat, fish, and vegetables. Their relatively low maintenance makes them popular among both professionals and serious home cooks. They are often chosen as a “standard” workhorse knife in Japanese kitchens.
Cultural Note: The kasumi finish is not just functional but aesthetic, symbolizing refinement and subtlety in Japanese craftsmanship. The mist-like boundary on the blade reflects the harmony between strength (hagane) and softness (jigane), embodying the duality central to Japanese blade-making tradition.

KIREAJI

Definition: KIREAJI means “sharpness” in Japanese.
Details: It expresses the essence of cutting cleanly and precisely, preserving the natural quality of ingredients.
Comparison: Unlike general terms for sharpness, KIREAJI also represents a deeper cultural value in Japanese craftsmanship.
Practical Use: The word is used as the name of our brand, symbolizing the pursuit of knives that deliver joy and efficiency in cutting.
Cultural Note: For more about our philosophy, see the Brand Story page.

Kissaki (Tip)

Definition:
Kissaki refers to the pointed tip of a knife blade, located at its very end. It is one of the most important structural parts of a knife, essential for precision and delicate cutting tasks.
Details:
The kissaki is sharp and pointed, enabling shallow incisions and detailed cuts. Its exact shape and sharpness vary depending on the knife type—for example, long and slender for sashimi knives, or slightly rounded in multipurpose knives. Because of its position and fine edge, it requires careful maintenance to prevent chipping.
Comparison:
Unlike the blade’s belly (ha-moto), which is suited for powerful, broader cuts, the kissaki excels in fine control. Western knives often use the tip for piercing, while Japanese knives emphasize precision and smooth separation of ingredients without crushing fibers.
Practical Use:
The kissaki is used for tasks such as slicing through meat or fish tendons, making fine incisions in vegetables or fruit, or performing decorative cuts. To keep it effective, regular sharpening at the correct angle is essential, as the tip is especially prone to wear.
Cultural Note:
In traditional Japanese cutlery and sword-making, the kissaki is a symbolic part of the blade. Its refinement demonstrates the craftsman’s skill, with its shape and sharpness reflecting both aesthetic beauty and functional mastery.

Kitaeji (Forged Steel Pattern)

Definition: Kitaeji refers to the traditional forging technique that produces layered patterns on the surface of Japanese knives. While it resembles what is internationally known as “Damascus steel,” kitaeji carries a distinct Japanese heritage and aesthetic.
Details: Created by laminating hard steel with softer layers, kitaeji combines durability with beauty. The process refines the steel, removes impurities, and results in wave-like or misty patterns along the blade surface.
Comparison: Unlike plain blades (honyaki or kasumi), kitaeji emphasizes visual artistry as well as performance. Compared to Western “Damascus,” kitaeji reflects a uniquely Japanese forging tradition rooted in swordsmithing.
Practical Use: Kitaeji blades are known for excellent sharpness, edge retention (often HRC 63–64), and relatively easy maintenance for professional chefs and serious enthusiasts.
Cultural Note: The layered kitaeji pattern is highly prized not only for its cutting ability but also as a symbol of craftsmanship—connecting modern knives with centuries of Japanese forging tradition.

Knife Engraving

Definition: Knife engraving refers to the process of inscribing characters, logos, or designs onto a knife’s surface to add personalization, identification, or decorative value.
Details: There are two main methods. Traditional hand engraving (Mei-kiri) uses a chisel-like tool called a tagane, giving the inscription a deep texture and handcrafted character, often preferred for kanji. Modern laser engraving employs a focused beam to create precise and versatile designs, including text and graphics, though the depth is usually shallower.
Comparison: Hand engraving offers a traditional, artisanal look with greater depth and uniqueness, while laser engraving provides speed, flexibility, and consistency. Both methods are durable, but the tactile quality of hand engraving is often more pronounced.
Practical Use: Engraving transforms a knife into a personal item, ideal for gifts, commemorations, or professional identification. Whether for chefs marking their tools or families celebrating milestones, an engraved knife carries added meaning while retaining full functionality.
Cultural Note: In Japan, engraved names on knives connect to centuries of tradition, echoing the signature marks (mei) left by swordsmiths on katana. This practice symbolizes pride in craftsmanship and continues to add cultural depth to modern Japanese knives.

Koba (Small Bevel)

Definition
Koba refers to the small secondary bevel applied just behind the main cutting edge of a Japanese knife. Although very narrow, it plays an essential role in balancing sharpness and durability.
Details
The Koba is typically ground at a wider angle (around 35–40°) than the primary edge (about 15–20°). This design strengthens the edge and reduces the risk of chipping, while still preserving the smooth and precise cutting ability for which Japanese knives are known. Properly crafted Koba also reduces friction, allowing ingredients to separate more cleanly during slicing.
Comparison
Unlike Western knives, which often rely on a single symmetrical double-bevel edge, Japanese knives with a Koba feature a dual-step edge structure. Compared to a razor-thin edge without Koba, the presence of this small bevel sacrifices a little ultimate sharpness but greatly improves edge stability, durability, and ease of maintenance.
Practical Use
For chefs and home cooks, the Koba extends edge life, makes sharpening easier, and enhances cutting comfort. When maintaining a knife, only the Koba needs to be retouched with a fine whetstone (#5000 grit or higher), making upkeep efficient while keeping performance high.
Cultural Note
The Koba reflects the Japanese philosophy of balancing sharpness with practicality. It embodies the craftsman’s pursuit of harmony between precision and durability, ensuring that knives can withstand daily use without compromising their legendary cutting ability. In traditional Japanese knife-making, adding Koba is considered a mark of skill and attention to detail.

Kuchigane (Ferrule)

Definition: A metal component located between the blade and handle of a knife, reinforcing the structure and improving hygiene and safety.
Details: Usually made of stainless steel or other rust-resistant metals, the kuchigane strengthens the connection between the handle and blade. In traditional Japanese knives (wa-bōchō), it is also referred to as a tsuba. Its design prevents gaps, which would otherwise allow water and dirt infiltration.
Comparison: Compared to knives without a ferrule, those with a kuchigane offer greater stability, durability, and sanitary performance. Wooden-handled knives especially benefit, as the ferrule protects against handle swelling, rotting, or loosening over time.
Practical Use: The kuchigane improves knife balance, prevents slipping during use, and ensures safe handling. Proper cleaning and drying are necessary since moisture and residue can accumulate at this junction. Regular inspection helps maintain stability; loose ferrules should be repaired or replaced to avoid accidents.
Cultural Note: In Japanese craftsmanship, the kuchigane symbolizes both functional reinforcement and aesthetic harmony between blade and handle. High-quality kuchigane enhances not only usability but also the perceived value of the knife.

Kuro-uchi (Black-Forged Finish)

Definition: Kuro-uchi refers to the traditional black finish left on Japanese knives when the forge scale (oxidized layer) is intentionally retained instead of being polished away.
Details: This finish gives the blade its distinctive dark, rustic appearance while providing a protective layer against rust. It also preserves the handcrafted character, with visible hammer marks often left on the surface.
Comparison: Unlike polished finishes (migaki), which emphasize a mirror-like shine, kuro-uchi highlights the natural state of forged steel. It is often contrasted with kasumi or mirror finishes, being the most rustic and traditional among them.
Practical Use: The black oxide film adds moderate rust resistance, reducing maintenance compared to bare carbon steel. Still, drying and proper care are essential. Kuro-uchi finishes are commonly seen on Santoku, Nakiri, and Deba knives, making them suitable for both professional and home kitchens.
Cultural Note: Kuro-uchi embodies the aesthetic of “wabi-sabi”—the Japanese appreciation of imperfection and natural beauty—while also reflecting the heritage of traditional blacksmithing.

M

Machi (Gusset)

Definition: The small step or gap found between the blade and the handle of a Japanese knife, serving structural, functional, and aesthetic purposes.
Details: Machi is positioned between the ago (heel corner of the blade) and the nakago (tang inside the handle). Its presence and size differ depending on the knife type—yanagiba and usuba often feature a visible machi, while deba and nakiri generally show little or none.
Comparison: In Western knives, blade length is typically measured from bolster to tip, while in Japanese knives it is measured from the machi to the kissaki (tip). This distinction means a “210 mm” yanagiba with a machi may have a shorter exposed edge compared to a Western counterpart of the same nominal size.
Practical Use: Machi contributes to durability and balance by reinforcing the connection between blade and handle. It also absorbs some stress during use, preventing cracking or loosening. Additionally, the presence of machi allows more precise re-handling or replacement of handles.
Cultural Note: Beyond function, machi is an aesthetic element in fine Japanese knives, often finished with care by the craftsman. Its subtle presence is appreciated by connoisseurs as a mark of authenticity and traditional construction.

Manganese

Definition: An alloying element in steel that enhances hardness, toughness, and wear resistance in knife blades.
Details: Manganese stabilizes the steel’s structure during heat treatment, helping refine grain size and prevent brittleness. It contributes to both durability and sharpness.
Comparison:
- Compared to carbon: adds toughness but less effect on sharpness.
- Compared to chromium: improves wear resistance rather than corrosion resistance.
- Compared to vanadium: provides balance without extreme hardness.
Practical Use: Steels like 65Mn (high-carbon manganese steel) are valued for durability and edge retention, often used in affordable yet high-performing knives.
Cultural Note: Modern Japanese knife makers sometimes adopt manganese steel, blending traditional forging with practical, cost-effective materials.

Magnesia Bonding Method

Definition: The magnesia bonding method is a manufacturing technique for artificial whetstones that uses magnesia cement as a binder, producing stones with distinctive properties.
Details: In this method, abrasive grains are mixed with magnesia cement (magnesium oxychloride), kneaded, and then hardened at room temperature without firing. The resulting stones absorb little water, allowing them to be used immediately without soaking. They provide strong grinding power, smooth sharpening performance, and are available in a wide range of grit levels. However, long-term soaking can damage the stone, and aging may lead to brittleness or cracks.
Comparison: Unlike vitreous-bonded whetstones, which are fired at high temperatures, magnesia-bonded stones are dried at room temperature, giving them superior immediate usability but lower long-term durability. Compared to resinoid-bonded whetstones, they offer stronger sharpening power but are more vulnerable to prolonged water exposure.
Practical Use: Magnesia-bonded whetstones are particularly popular as finishing stones due to their smooth sharpening feel. They are well suited for fine edge refinement but require careful handling, including thorough drying and proper storage, to ensure longevity.
Cultural Note: In Japan’s knife-making and sharpening culture, magnesia-bonded stones are valued for their efficiency and refined sharpening touch. Professional chefs and sharpeners often select them when precision and speed are required, despite their relatively shorter lifespan compared to other bonded stones.

Magnolia Wood (Hōno-ki)

Definition: Magnolia wood, known as Hōno-ki in Japanese, is a lightweight and durable wood traditionally used for knife handles. Its properties make it especially well suited for Japanese kitchen knives.
Details: This wood is resistant to water and decay, even in humid conditions. It is easy for craftsmen to process and shape, producing smooth, ergonomic handles. Its pale color and subtle grain also enhance the knife’s visual elegance without distracting from the blade.
Comparison: Compared to heavier woods like ebony or rosewood, magnolia is lighter and more comfortable for long use, though it is less dense and offers a simpler appearance. When paired with water buffalo horn at the ferrule, it combines functionality with durability and aesthetic refinement.
Practical Use: Magnolia wood is most often found on traditional Japanese knives such as deba, usuba, and yanagiba. Its comfortable grip and light weight allow chefs to work for extended periods with reduced fatigue, while its water resistance ensures reliability in kitchen environments.
Cultural Note: In Japanese knife-making, magnolia handles represent a balance between practicality and tradition. Many professional chefs value them for their understated elegance and their connection to centuries of Japanese craftsmanship.

Medium Whestone

Definition: Nakato refers to a medium-grit whetstone, typically ranging from #1000 to #3000, used for maintaining and refining knife edges. It plays a central role in everyday knife care.
Details: Positioned between coarse stones (arato) and fine finishing stones (shiageto), Nakato strikes a balance between sharpening power and control. It smooths out rough edges from coarse grinding and restores sharpness without removing excessive material.
Comparison: Compared to coarse stones, Nakato does not aggressively reshape the blade but provides finer refinement, making it better suited for regular maintenance. Unlike finishing stones, it does not create a polished edge, but instead prepares the blade for either daily use or final honing.
Practical Use: Nakato is the most frequently used whetstone in both home and professional kitchens. A #1000 grit stone is ideal for restoring dull knives, while a #3000 grit stone is effective for routine upkeep when knives are sharpened often. Both synthetic and natural variants exist: synthetic stones offer consistency and ease of use, while natural stones give a more nuanced finish.
Cultural Note: In Japanese sharpening tradition, Nakato is considered the “workhorse” stone. Its importance lies not in glamour but in reliability, forming the foundation of sharpness for Japanese knives and embodying the discipline of routine maintenance valued by Japanese chefs.

Types of Whetstones

Mennaoshi (Whetstone flattening)

Definition: A maintenance process that restores a whetstone’s surface to a flat state, ensuring consistent and effective knife sharpening.
Details: Over time, whetstones develop depressions in frequently used areas, leading to uneven sharpening. Mennaoshi involves grinding down these high and low spots to restore a level surface. This not only improves sharpening accuracy but also extends the lifespan of the whetstone.
Comparison: Unlike standard sharpening, which works on knives, mennaoshi is performed on the whetstone itself. Specialized flattening stones (often coarse-grit) are used, differing from correction whetstones in that their sole purpose is surface leveling.
Practical Use: The process involves applying water to both stones, then rubbing the whetstone against a flattening stone in circular or back-and-forth motions until flat. Afterward, both stones should be rinsed and air-dried slowly to prevent cracking. Regular mennaoshi keeps whetstones efficient and reliable.
Tools: Flattening stones, water for lubrication and debris removal, and sometimes diamond plates for faster or more precise flattening.

Mine (Spine)

Definition
The Mine refers to the spine, or back of the knife, located opposite the cutting edge. It is not sharpened and provides structural balance and strength to the blade.
Details
The Mine is usually straight or gently curved and made from the same steel as the rest of the blade. In high-quality knives, it is carefully finished to improve comfort, balance, and visual appeal. Because it is thicker than the edge side, the spine contributes to durability and overall knife stability.
Comparison
Unlike the cutting edge, which is thin and sharp, the Mine is blunt and sturdy. In contrast to Western knives, where the spine is often purely structural, Japanese knives frequently utilize the spine for food preparation tasks such as scraping or pounding. This makes the Mine a more functional element in traditional Japanese cutlery.
Practical Use
The Mine can be used for light pounding, such as tenderizing meat, or for scraping ingredients like burdock root (gobo) without damaging their texture. It also provides a safe side for pressing against the hand during controlled cutting, adding both safety and versatility.
Cultural Note
In Japanese craftsmanship, even the Mine is polished with care, reflecting the artisan’s dedication to detail. Its finish is considered part of the knife’s beauty and usability. The use of the Mine in food preparation techniques further illustrates the Japanese philosophy of maximizing every part of the blade.

Mirror Polished

Definition: Mirror polishing is a finishing technique that creates a highly reflective, smooth surface on the blade of a knife. It is valued for both its functional benefits and its luxurious appearance.
Details: By carefully grinding and polishing with progressively finer abrasives, the blade achieves a glass-like surface. This smooth finish reduces friction during cutting, minimizes food adhesion, and improves rust resistance, particularly in carbon steel knives.
Comparison: Compared to satin or brushed finishes, mirror polishing provides superior resistance to rust and food sticking, but requires more time, skill, and maintenance. While less forgiving of scratches, it offers a higher degree of refinement and performance.
Practical Use: Mirror-polished knives glide through ingredients with minimal resistance, producing clean, precise cuts without tearing fibers. They are especially appreciated by chefs handling sashimi or delicate garnishes. Proper drying and storage are essential to preserve the polish over time.
Cultural Note: In Japanese knife-making, mirror polishing is regarded as a mark of craftsmanship, reflecting the artisan’s dedication and skill. Beyond functionality, it symbolizes refinement and respect for the ingredients, aligning with the Japanese culinary philosophy of honoring food through precise preparation.

Mizuyaki (Water Quenching)

Definition: Mizuyaki, or water quenching, is a traditional heat-treatment method in Japanese knife-making where heated steel is rapidly cooled in water to increase hardness and sharpness.
Details: By cooling steel from around 800–900°C in water, the crystal structure transforms into martensite, producing exceptional hardness. However, the sudden temperature change also introduces risks of cracking or warping, requiring great skill from the craftsman. Knives treated with mizuyaki are prized for their superior edge retention and characteristic beauty.
Comparison: Compared to oil quenching, water quenching produces harder steel and sharper edges but carries a higher risk of failure. Oil quenching is more stable and easier to control, while mizuyaki is considered the more traditional and demanding method, often reserved for high-end blades.
Practical Use: Water-quenched knives are exceptionally sharp and durable, making them ideal for tasks requiring precision, such as sashimi slicing. They often display a distinctive hamon (wave-like pattern), which enhances both functionality and appearance. Proper care, such as drying and oiling, is essential to prevent rusting.
Cultural Note: In Japan, mizuyaki is deeply connected to swordsmithing traditions and is regarded as a hallmark of true craftsmanship. The technique symbolizes mastery and dedication, linking modern kitchen knives to the heritage of Japanese sword-making.

Mizuyaki vs Aburayaki

Molybdenum

Definition: Molybdenum is an alloying element commonly added to knife steel, especially stainless steel, to improve corrosion resistance, wear resistance, and overall durability.
Details: When blended into steel, molybdenum enhances toughness, reduces brittleness, and allows the blade to maintain hardness even after repeated use. Its presence is particularly valuable in humid environments, as it strengthens the steel’s resistance to rust.
Comparison: Unlike carbon, which directly increases hardness and sharpness, molybdenum acts as a stabilizer, balancing strength with corrosion resistance. When combined with vanadium, it further improves wear resistance and cutting performance, making it especially effective in stainless steels.
Practical Use: Knives containing molybdenum are easy to maintain, durable, and often reasonably priced. They deliver smooth cutting performance suitable for both home and professional kitchens. Beyond kitchen knives, molybdenum steel is also trusted in medical instruments like scalpels for its precision and cleanliness.
Cultural Note: In modern Japanese knife-making, molybdenum has become a standard component in stainless steel knives. Its introduction reflects the blending of traditional Japanese craftsmanship with modern metallurgy to meet the needs of global chefs.

Mukimono (Peeling Knife)

Definition: Mukimono is a traditional Japanese peeling knife designed for delicate tasks such as peeling vegetables and fruits or making decorative cuts.
Details: With its slender blade and sharp tip, Mukimono excels at precision work. It is lightweight and easy to maneuver, reducing fatigue during extended use. The fine edge preserves the texture of ingredients while allowing clean, smooth cuts.
Comparison: Unlike larger multipurpose knives such as Santoku or Gyuto, Mukimono is specialized for precision rather than heavy cutting. It is closer in function to Usuba but lighter and designed specifically for tasks like katsuramuki (thin rotary peeling) or ornamental carving.
Practical Use: In professional kitchens, Mukimono is essential for peeling and intricate garnishes. It is particularly valued in Japanese cuisine, where ingredient presentation is as important as flavor. For home cooks, it offers precision control for small vegetables and fruits.
Cultural Note: Mukimono is central to the art of decorative food preparation in Japan, where visual beauty enhances culinary experience. Its use reflects the Japanese emphasis on harmony between taste and aesthetics, making it not just a tool but also a symbol of culinary artistry.

Usuba

N

Nakago (Tang / Core)

Definition: The part of the knife blade that extends into the handle, serving as the structural core that connects blade and handle.
Details: The nakago is a metal rod embedded in the handle, typically narrowing and tapering toward its end. It is essential for the knife’s structural integrity and balance. In traditional Japanese knives, the nakago often carries the bladesmith’s signature, marking authenticity and lineage.
Comparison: Western knives often use a full tang (extending the full length and width of the handle), while Japanese knives may use a partial tang. Both designs influence durability, balance, and handling. A well-crafted nakago is crucial for strength and long-term use.
Practical Use: The nakago provides reinforcement, balance adjustment, and identification. For chefs and serious users, selecting a knife with a properly designed and securely mounted nakago ensures better control, longer durability, and cultural value through the artisan’s mark.

Nakakojiri (Tang End)

Definition: Nakakojiri refers to the end portion of the tang, located at the bottom of the handle. It is a structural element that directly affects a knife’s strength, balance, and overall usability.
Details: Positioned where the tang meets the handle base, nakakojiri often has a hollow or semi-hollow form. This design not only secures the blade firmly to the handle but also adjusts the knife’s weight distribution, reducing wrist fatigue and improving comfort during extended use.
Comparison: While Western knives often rely on full tangs with riveted handles for stability, traditional Japanese knives use a hidden tang structure where parts like the nakakojiri play a critical role in balance and weight reduction. This distinction reflects the Japanese emphasis on lightness and precision over sheer mass and durability.
Practical Use: A well-constructed nakakojiri ensures the knife feels stable yet lightweight, allowing chefs to work efficiently during long cooking sessions. Its sealed structure also protects against moisture and dirt entering the handle, extending the knife’s lifespan.
Cultural Note: The design of nakakojiri reflects Japan’s tradition of blending ergonomics with craftsmanship. By focusing on details like balance and ease of use, artisans create knives that embody both functionality and the Japanese aesthetic of refinement.

Nakiri (Vegetable Knife)

Definition: The Nakiri is a traditional Japanese kitchen knife designed specifically for cutting vegetables, characterized by its straight edge and squared tip.

Details: Typically ranging from 165mm to 210mm in blade length, the Nakiri is double-edged and easy to handle for both right- and left-handed users. Its wide, flat blade ensures vegetables are sliced cleanly without crushing fibers, preserving texture and appearance.

Comparison: Unlike the Usuba, another Japanese vegetable knife that is single-beveled and suited for professional chefs, the Nakiri’s double-beveled design makes it more accessible and user-friendly. Compared to all-purpose knives such as the Santoku, the Nakiri is less versatile but excels in vegetable preparation.

Practical Use: The Nakiri is ideal for chopping, slicing, and julienning vegetables in large volumes. Its broad surface also allows easy transfer of ingredients from the cutting board to cookware. However, it is not suited for meat, fish, or fine tasks such as deboning, where more specialized knives are required.

Cultural Note: The Nakiri became popular in Japanese households during the Edo period, when vegetable-based diets were common. It remains a staple in Japanese kitchens, symbolizing the precision and respect given to vegetable preparation in traditional cuisine.

Usuba vs Nakiri
Related websites
Explore Premium Usuba Knives for Precise Vegetable Cuts | KIREAJI

Natural whestone

Definition: A natural whetstone is a sharpening stone formed over thousands or millions of years from natural mineral deposits, traditionally used in Japan to refine the edges of high-quality knives.
Details: Composed mainly of quartz and other minerals, natural whetstones provide gentle abrasiveness that sharpens without removing excessive steel. They produce a distinctive misty finish (kasumi) on the blade, prized by artisans and chefs for its refined appearance and smooth edge.
Comparison: Unlike synthetic whetstones, which offer uniform grit and predictable results, natural whetstones vary in hardness, density, and sharpening feel depending on their quarry. This variation can produce unique results but requires more skill to handle. Synthetic stones are more affordable and consistent, while natural stones are valued for the individuality of their sharpening qualities.
Practical Use: Natural whetstones are often used as finishing stones, capable of creating razor-sharp edges and elegant kasumi finishes. However, they require more experience to use effectively and are typically chosen by professionals or serious enthusiasts. Proper drying and careful storage are essential to prevent cracking.
Cultural Notes: Kyoto has long been famous for producing Japan’s finest natural whetstones, with eastern stones known for hardness and precision, and western stones for softer, more forgiving sharpening. The use of natural stones connects modern knife sharpening with centuries of Japanese craftsmanship and tradition.

Types of Whetstones

Nihonkou (SK4)

Definition: SK4 is a Japanese carbon steel containing about 0.9% carbon. It is commonly referred to simply as “Japanese steel” in the context of knives, known for its sharpness and ease of sharpening.
Details: With relatively high carbon content, SK4 achieves excellent hardness and edge retention while remaining easy to sharpen. It offers smooth, precise cutting but, like most carbon steels, is prone to rust if not properly maintained.
Comparison: Compared to advanced steels such as Aogami (Blue Steel) or Ginsan, SK4 is more affordable and easier to sharpen, though it lacks the extreme edge retention or corrosion resistance of those steels. This makes it a practical choice for everyday use, balancing performance and cost.
Practical Use: SK4 knives are valued by both professional chefs and home cooks. They require diligent care—thorough drying and occasional oiling—but reward the user with reliable sharpness and a comfortable sharpening experience. They are particularly suited to those who appreciate the feel of traditional carbon steel.
Cultural Notes: SK4 has long been used by Japanese craftsmen in making affordable yet high-quality knives. Its balance of sharpness, ease of care, and cost-effectiveness has made it a popular entry point into the world of Japanese cutlery, connecting modern kitchens with traditional knife-making heritage.

Experience the sharpness trusted by 98% of Japan’s top chefs — handcrafted in Sakai City.

Through our exclusive partnership with Shiroyama Knife Workshop, we deliver exceptional Sakai knives worldwide. Each knife comes with free Honbazuke sharpening and a hand-crafted magnolia saya, with optional after-sales services for lasting confidence.

All Japanese Knives from Sakai

KIREAJI's Three Promises to You

1. Forged in the Legacy of Sakai
From Sakai City—Japan’s renowned birthplace of professional kitchen knives—each blade is crafted by master artisans with over six centuries of tradition. Perfectly balanced, enduringly sharp, and exquisitely finished, every cut carries the soul of true craftsmanship.
2. Thoughtful Care for Everyday Use
Every knife includes a hand-fitted magnolia saya for safe storage. Upon request, we offer a complimentary Honbazuke final hand sharpening—giving you a precise, ready-to-use edge from day one.
3. A Partnership for a Lifetime
A KIREAJI knife is more than a tool—it is a lifelong companion. With our bespoke paid aftercare services, we preserve its edge and beauty, ensuring it remains as precise and dependable as the day it first met your hand.

Country/region

Language