White Steel #2
Where traditional sharpness begins.
Made from ultra-pure carbon steel, White Steel #2 offers razor-sharp edges that respond instantly to the whetstone. Its clarity and control make it ideal for chefs who value precision and the authentic feel of Japanese blades.
White Steel #1
Refined sharpness, elevated.
With higher carbon content than White Steel #2, White Steel #1 delivers a finer edge that lasts longer. It rewards skilled hands with unmatched precision, making it the choice for those who accept nothing less than excellence.
Blue Steel #2
Strength for the everyday professional.
Alloyed with tungsten and chromium, Blue Steel #2 balances keen sharpness with added durability and wear resistance. Trusted in busy kitchens, it delivers consistent performance service after service.
Blue Steel #1
Sharpness at its highest form.
Enriched with tungsten and chromium, Blue Steel #1 achieves superior hardness and edge longevity. Demanding yet rewarding, it is favored by master chefs who require flawless performance at the highest level.
Super Steel (Honyaki)
A sword in the kitchen.
Forged from a single piece of steel and meticulously heat-treated, Honyaki represents the pinnacle of Japanese bladesmithing. Each blade embodies unrivaled sharpness, elegance, and the spirit of the artisan’s craft.
ZDP189
The cutting edge of innovation.
Created through advanced powder metallurgy by Proterial (formerly Hitachi Metals), ZDP189 achieves extreme hardness, exceptional edge retention, and rust resistance. A next-generation steel, it is trusted by leading chefs worldwide.
Ginsan
Stainless steel with a soul.
Developed by Proterial (formerly Hitachi Metals) and hand-forged by skilled artisans, Ginsan combines the sharpness of carbon steel with stainless ease. Its durability, rust resistance, and chip resilience make it a favorite for daily cooking.
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2. Why the World Embraced Stainless Steel
Outside Japan, stainless steel became the standard for practical reasons. It resists rust, suits fast-paced kitchens, and adapts well to mass production. Western cooking often emphasizes durability over razor-thin precision, making stainless an obvious choice.
In Japan, however, where cuisine values finesse and refinement, carbon steel aligns more closely with culinary ideals. -
4. A Knife That Grows With Its Owner
Carbon steel requires care—wiping, drying, regular sharpening. But in return, it develops a patina and character unique to each owner. Over time, the knife reflects its user’s habits and devotion, forging an emotional bond that stainless rarely inspires.
Beyond Sharpness: Why Japanese Knives Carry a Soul
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Japanese knives are more than cutting tools—they embody centuries of craftsmanship, the spirit of the samurai, and a uniquely personal relationship between chef and blade.
Carbon steel delivers exceptional sharpness, develops a patina that reflects its owner’s journey, and invites a daily sharpening ritual that deepens both skill and appreciation.
What emerges is not just performance, but a soulful connection that grows stronger with every use.
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The Invisible Shield: Passive Film
When chromium (13% or more in most Japanese steels) reacts with oxygen, it forms an invisible oxide layer on the blade’s surface. This passive film blocks moisture and oxygen, preventing the red rust that quickly destroys ordinary steel.
What makes it extraordinary is its self-healing ability: if the blade is scratched, the film instantly reforms, giving the steel a second skin of protection.
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Science Meets Craftsmanship
Japanese stainless steel knives are more than rust-resistant tools. They are the fusion of metallurgy and tradition, crafted by artisans who refine the steel’s potential through generations of skill. Each blade is proof that science and craftsmanship together can create beauty that lasts a lifetime.
The Science Behind the Shield: Why Japanese Stainless Steel Defies Rust
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Japanese stainless steel forms an invisible, self-repairing protective layer that reacts instantly with oxygen, giving the blade exceptional rust resistance without compromising sharpness.
With higher chromium content than standard Western steels, these blades maintain a superior balance of durability and cutting performance.
Still, this resilience is not limitless—proper hand-washing and drying are essential to keep the passive film strong and protect the knife for years to come.
Q1. What does “knife steel” actually mean?
Knife steel refers to the type of metal used to craft the blade—the very foundation of a knife’s performance. In Japanese knives, the steel determines sharpness, ease of sharpening, rust resistance, and durability. Broadly, steels fall into two categories: carbon steel and stainless steel, each with distinct advantages that shape how the knife feels and performs in daily use.
Q2. What’s the difference between carbon steel and stainless steel?
Carbon steels such as Shirogami (White Steel) and Aogami (Blue Steel) are celebrated for their unmatched sharpness and the ease with which they can be resharpened. However, they are more vulnerable to rust and demand attentive care. These steels have long been favored by professional chefs and artisans who value ultimate cutting performance. Stainless steels, by contrast, offer excellent rust resistance and easier day-to-day maintenance. Thanks to modern metallurgy, premium stainless steels such as Ginsan now deliver sharpness once thought possible only in carbon steel, making them increasingly popular among professionals and home cooks alike.
Q3. Is “sharpness” the same as “ease of sharpening”?
Not quite. Sharpness describes how effortlessly a knife slices through ingredients, while ease of sharpening refers to how readily the blade regains its edge during maintenance. Carbon steels excel in both—they achieve razor-like sharpness and can be quickly restored on a whetstone. Stainless steels, while more convenient for everyday use, often retain their edge longer but may be more challenging to sharpen by hand, depending on the alloy.
Q4. Why are there so many types of Japanese knife steel?
Japanese knives are not merely tools but the result of centuries of culinary culture and craftsmanship. Over generations, blacksmiths have developed a wide range of steels, each tailored to specific cutting tasks, climates, and user preferences. This diversity reflects Japan’s dedication to refining performance to meet the exacting demands of professional cuisine and to honor the philosophy of constant improvement.
Q5. Does sharpening technique matter more than steel quality?
In many ways, yes. Even the finest steel cannot perform at its peak without proper sharpening. Conversely, a modest steel in the hands of someone skilled with a whetstone can achieve outstanding results. Steel provides the foundation, but true sharpness comes from technique and care—the dialogue between blade and user.
Q6. How do I choose the right steel for me?
The best choice depends on your cooking style and values. If you prefer low-maintenance convenience, stainless steel is often ideal. If you enjoy the satisfaction of sharpening your own blade and demand peak performance, carbon steel may be your match. At KIREAJI, we provide detailed information and expert guidance to help you make the right choice, so you can confidently find the steel that best complements your skills, habits, and passion for cooking—even when shopping online.
Japanese Knife Materials
The steel behind a Japanese knife defines its sharpness, durability, and care. From traditional carbon steels like White #2 and Blue #2 to modern innovations such as Ginsan and ZDP189, each material offers its own balance of performance and maintenance. This guide explores how these choices shape the knives we use today.
