In essence, a kitchen knife is simply a piece of steel with a handle. A good kitchen knife is made of steel, and understanding the Japanese knife steel types is essential for choosing the right one. Good steel should be considered as a base — a potential which, through the processes of forging, bending, and shaping the blade, can only be exploited by experienced craftsmen.

There are three main Japanese knife steel types used in the manufacture of kitchen knives. Each category has its advantages and disadvantages, depending on the use of the knife:

• High Carbon Steels (Traditional Japanese Steels)
• Corrosion-Resistant Steels (VG10 steel knife)
• Powder Steels (ZDP-189 or R2)

Before diving into different Japanese knife steel types, let's first explore the main chemical elements of steel and their effect on the characteristics of the kitchen knife.

Chemical Elements in Steel and Their Effect:

Steel is made up of iron (Fe), carbon (C), and smaller amounts of other elements. Carbon (C) is the key element in steel. Without carbon, steel could not be forged or bent. More carbon means harder steel. Steel can contain between 0.1% and 3% carbon.

Key Elements:

• Iron (Fe): Main steel element.
• Carbon (C): Key element that enables steel hardening during heat treatment. It reduces corrosion resistance and makes steel brittle.
• Chromium (Cr): Greatly increases corrosion resistance; also improves hardness.
• Manganese (Mn): Improves structure and allows further hardening.
• Vanadium (V): Increases hardness, sharpness, and edge retention.
• Molybdenum (Mo): Boosts corrosion resistance and maintains strength during temperature changes.
• Silicon (Si): Enhances carbon’s effects, improving hardness.
• Cobalt (Co): Adds hardness and corrosion resistance.
• Tungsten (W): Improves wear resistance.
• Phosphorus (P) and Sulfur (S): Impurities present in small amounts.

A Honyaki knife is one of the most demanding blades a craftsman can produce. Made in Japan by a few highly skilled blacksmiths, it follows a traditional hardening method inspired by the forging of the katana.

Unlike most Japanese kitchen knives, which are constructed from multiple layers of steel, a Honyaki blade is forged from a single piece of high-carbon steel. The differential heat treatment process creates a hardened cutting edge and a softer spine, resulting in exceptional sharpness, edge retention, and cutting performance.

Because of the technical difficulty and the high risk of failure during production, very few artisans are capable of making true Honyaki knives. Each blade requires precision, experience, and absolute control during heat treatment. For this reason, production remains extremely limited.

For collectors and serious enthusiasts of Japanese craftsmanship, a Honyaki knife represents the highest expression of the blacksmith’s art. The price reflects not only the materials, but the years of experience required to master such a demanding process.

White steel is an extremely pure Japanese knife steel type with a high percentage of carbon and no additional ingredients (it may contain phosphorus (F) and sulfur (S) as impurities). There are two types of white steel: white steel 1 and white steel 2. Forging white steel is extremely difficult and requires highly skilled craftsmen. A knife made from this steel has an extremely sharp edge, but it is brittle and susceptible to cracking.

White steel no.1 contains iron (Fe), carbon (C) 1.25-1.35%, manganese (Mn) 0.20-0.30%, phosphorus (P) 0 .03%, sulfur (S) at 0.004% and silicon (Si) at 0.10 to 0.20%. It is very popular with professional chefs preparing traditional Japanese cuisine because it can be refined to an extremely fine edge. It has a very good cutting edge and is easy to resharpen.

White steel no.2 contains iron (Fe), carbon (C) 1 – 1.15%, manganese (Mn) 0.20 – 0.30%, phosphorus (P) 0.03%, sulfur (S) 0.004% and silicon (Si) 0.10 – 0.20%. It has minimal impurities and a very fine grain structure, so it is ideal for fine cutting tools such as traditional Japanese-style knives. It also has very good cut retention and is very easy to resharpen. Recommended for new users of traditional Japanese knives.

By adding chromium (Cr) to steel, we increase its resistance to corrosion. Chromium oxide forms a protective film on the surface of the steel, which prevents any contact between iron and water or oxygen. If the base steel alloy contains 12% or more chromium, we call it stainless steel. Even stainless steel kitchen knives should be wiped dry after use, especially if you are cutting fruits and vegetables that contain acids (lemon, onions, tomatoes, etc.). If we leave the knife dirty and wet for a long time, even the stainless steel can corrode.

Due to technological development, we have witnessed the emergence of new types of steels, which combine the quality of steel with a high percentage of carbon and the practicality of corrosion-resistant steel. High carbon (C) and corrosion resistant steels are popular with professional chefs today.

This Japanese knife steel type contains iron (Fe), carbon (C) 1.40 – 1.50%, chromium (Cr) 0.30 – 0.50%, manganese (Mn) 0.20 – 0.30%, molybdenum (Mo) 0.30 – 0.52% and phosphorus (P) 0.03%, sulfur (S) 0.004%, silicon (Si) 0.10-0.20%, tungsten (W) 2.00 – 2.50% and vanadium (V) 0.30 – 0.50%.

It is one of the greatest Japanese carbon steels in terms of performance. In addition to containing more carbon, chromium and tungsten than blue steel No.1, it also contains molybdenum. It has very good sharpness and excellent edge retention. It is also capable of reaching high hardness without being brittle. Therefore, many knife enthusiasts rank aogami super among the best high carbon steels in the world.

Very high hardness up to 67 on the Rockwell C scale (HRC) and good toughness.

Satisfactory corrosion resistance.

Easy to sharpen steel, with a fine microstructure for a fine edge and the ability to stay sharper longer than other traditional steels.