Material of Knife

  • KIREAJI knives are meticulously handcrafted one by one by skilled artisans in Sakai City. However, the true charm of KIREAJI knives lies not only in the quality of the steel. What truly defines the quality of a knife is how meticulously the three key processes—forging, heat treatment, and sharpening—are carried out, and how well the selected steel harmonizes with these processes.

  • Even when the same steel is used, there can be significant differences in quality. For example, Japanese knives typically go through up to 20 detailed steps before heat treatment. To reduce costs, this number may be cut down to 12, while a more meticulous process could involve 30 steps. These differences in the manufacturing process can have a major impact on the final quality of the knife.

  • At KIREAJI, we offer more than just tools—we provide “partners” that enrich your cooking experience. Carefully crafted by skilled artisans, KIREAJI knives are valuable tools that will be cherished and used for a long time, making your time in the kitchen even more special.

  • What Makes a Good Knife?

  • We’d like to share some insights on what defines a good knife. In this article, we will outline three key aspects that contribute to the quality of a knife: sharpness and maintenance. While everyone has their own preferences regarding knives, understanding these core elements can help you make an informed decision when choosing the perfect blade for your needs.

  • 1. Sharpness

    The sharpness of a knife can be broken down into three factors:

    • Ease of entry: How easily the blade pierces the food.
    • Smoothness of cut: How seamlessly the blade progresses through the food.
    • Edge retention: How long the knife maintains its sharpness.

    The concept of sharpness is uniquely understood in Japanese culture. Unlike in English, where sharpness is often simply referred to as "sharp," Japanese culinary traditions explore the nuances of how a knife cuts food, such as how it enters and moves through the material. The longevity of sharpness is especially important; a knife that holds its edge for a long time is generally considered to be of higher quality.

  • 2. Maintenance

    Maintenance is crucial for keeping a knife in top condition and includes three main factors:

    • Resistance to rust: Stainless steel knives are more resistant to rust, making them ideal for home kitchens.
    • Ease of sharpening: A knife that sharpens easily allows you to maintain its ideal cutting edge with minimal effort.
    • Durability: The knife’s ability to resist chipping, especially in more expensive blades, ensures it remains functional for a longer time.

    One additional, often overlooked aspect of maintenance is emotional attachment. If you love your knife, you’re more likely to take good care of it. This personal connection can lead to more attentive maintenance and care, ensuring the longevity of the blade.

  • A great knife is defined by a combination of sharpness, maintenance, and balance. While these elements are the foundation of quality, personal preference plays a significant role in determining the right knife for you. Whether you prioritize long-lasting sharpness, ease of care, or perfect balance, understanding these factors will help you choose a knife that fits your needs and enhances your culinary experience.
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Super Steel (Honyaki)

The collection showcases Super Steel (Honyaki) knives, known for their sharpness and durability. Crafted by Sakai City craftsmen, these knives are favored by chefs for their quality and craftsmanship.

Super Steel (Honyaki)
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Blue Steel #1

The Blue Steel #1 collection introduces knives made from Blue Steel, enhanced with chromium and tungsten for better wear resistance. These knives offer high carbon content for sharp cutting abilities.

Blue Steel #1
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Blue Steel #2

The Blue Steel #2 collection features knives made from a specially formulated steel that includes tungsten and chromium for improved wear resistance and sharpness retention.

Blue Steel #2
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White Steel #2

The White Steel #2 collection presents knives crafted from pure White Steel, known for minimal impurities and excellent sharpness. Ideal for creating finely honed edges, this material is particularly valued for its ease of sharpening. These knives are designed for those who prioritize precision cutting and easy maintenance in their culinary tools.

White Steel #2
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ZDP189

The ZDP189 collection introduces knives crafted from ZDP189 stainless steel, notable for its exceptional hardness and sharpness retention. This high purity is achieved through powder metallurgy by Hitachi Metals. The material's robustness, durability, and corrosion resistance make these knives favorites among professional chefs and enthusiasts. Each knife is carefully handcrafted by master craftsmen, ensuring unparalleled quality and performance.

ZDP189

Ginsan

The Ginsan collection showcases knives made from Hitachi Metals' Ginsan stainless steel, celebrated for its rust resistance and a fine balance between sharpness and durability. This steel, with high carbon content and hardness, rivals traditional carbon steel in cutting performance. Forged by traditional craftsmen, including Shougo Yamatsuka, these knives emphasize the significance of the forging process in enhancing the blade's strength, sharpness retention, and chip resistance.

Ginsan

  • The Moment Steel Comes to Life: The Passion and Rhythm of a Blacksmith

  • In the moment when the steel, engulfed in flames, glows a vivid orange, the passion and mystery of the blacksmith’s craft are brought to life. It’s not precise measurements, but the trained eye of the blacksmith that gauges the heat and color. That bright orange hue signals the ideal temperature, making the steel supple and ready to be shaped.

  • In blacksmithing, rhythm matters more than sheer force. Holding the hammer lightly, staying relaxed, and maintaining a steady rhythm is key to transferring just the right amount of energy to the steel. If you rush or strike hastily, the steel becomes hard and resistant, refusing to yield to form. Blacksmithing is an art of "height" and "weight"—raising the hammer high, letting its weight come down slowly. This measured, rhythmic strike coaxes the steel into its desired shape.

  • The color of the steel, seen in the dim light of the forge, has a depth entirely different from daylight. Capturing the brief, bright orange before it cools to black is essential, knowing just when to halt the hammer. For a blacksmith, reading these subtle color shifts is a moment of breathless anticipation.
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Japanese Knife Materials

In the realm of Japanese knives, the choice of material plays a crucial role in performance and maintenance. This guide delves into the nuances of carbon and stainless steel, including popular variants like White Steel #2 and Blue Steel #2, and newer innovations like ZDP189 and Ginsan. Understand the trade-offs between sharpness, durability, and ease of care to select the ideal knife material for your cooking style.

Japanese Knife Materials

FAQ About Material of Knife

What's the difference between carbon steel and stainless steel?

The main differences are:

Carbon Steel:

  • Achieves high hardness and sharp cutting edge
  • Prone to rusting
  • Requires maintenance but easy to sharpen

Stainless Steel:

  • Resistant to rust and easy to maintain
  • Generally doesn't achieve the sharpness of carbon steel but lasts longer
  • Can be more difficult to sharpen



What is high-carbon stainless steel?

High-carbon stainless steel is an alloy that contains more carbon in stainless steel. It aims to combine the rust resistance of stainless steel with the high hardness and sharpness of carbon steel. However, it doesn't perfectly combine all the advantages of both.

What does the hardness (HRC) of a knife mean?

HRC stands for Rockwell Hardness (C scale), which is an indicator of steel hardness. Typical knife hardness ranges are:

  • Soft: 50-54 HRC
  • Medium: 55-58 HRC
  • Hard: 59-62 HRC
  • Very Hard: 63+ HRC

Harder steel can achieve a sharper edge but tends to be more brittle. Softer steel has higher toughness and is less prone to chipping.

What should I be careful about when maintaining knives made of different steels?

Consider the following for different steel types:

  • Carbon Steel: Wash and dry immediately after use. Apply oil regularly.
  • Stainless Steel: Normal care is sufficient, but avoid soaking in water for long periods.

Video Provided: Japan Traditional Crafts Aoyama Square (YouTube)

  • Be Cautious with Inexpensive Knives

  • Buying a cheap knife may mean that the steel used is of low quality. Low-quality steel tends to lose its sharpness quickly, which can ultimately reduce the efficiency of your cooking tasks.

    At KIREAJI, we provide authentic Japanese knives crafted by trusted craftsmen from knife-making workshops in Sakai City. Each knife is handcrafted with care, ensuring you receive a reliable and high-quality product that brings peace of mind.