A Hitachi Metals ltd. is one of the main manufacturers of high quality metals and materials in Japan.

It is known as the YSS “Yasuki hagane” (Yasuki Special Steel) manufacturer for the cutlery industry. The Yasuki city is located in the Shimane Province, where hagane steel was handmade since ancient times and used for the Japanese swords production.

On this post, we explain the characteristics of each steel.


White steel – Shirogami
It is basically refined carbon steel with no other ingredients and used to manufacture special knives, planers, chisels, etc. From this material, a blade with good cut and easy to be sharpened can be made if it is forged into proper temperatures and modes.

The white steel is subdivided in no.1, no.2, no.3 according to the composition of the table below.

Used to manufacture special knives, planers, chisels, etc.

Blue steel – Aogami
It is made from the chromium addition and tungsten to white steel (shirogami), making the cutting edge more durable. The expensive knives are usually made from this material. The blue steel is also subdivided into no.1, no.2, no.3, according to the carbon proportion.

Once the cutting and hardness are chosen, the carbon quantity is decreased, but if the resistance is chosen, the carbon quantity is increased. The material is chosen based on the purpose of each knife or blade.

Blue steel super – Aogami super
It is the best of the 3 steels. It has a high percentage of carbon and chromium that increases the hardness and durability of the cutting edge.




Molybdenum Vanadium: the alloy addition increases the resistance against rust and the durability of the cutting edge.

VG10: increases the resistance against rust.

Gin-san (silver 3): it is a durable cutting edge stainless steel, also manufactured by Hitachi, such as Shirogami and aogami carbon steels. Because of the addition of carbon, the cutting edge durability has increased almost as much as the shirogami and aogami, and there is also the advantage of being resistant to rust.

A-10: increasing the percentage of carbon also increases the blade durability. Although this material is developed by the process of heating and cooling almost instantly, it is flexible.

Cobalt: it is one of the best stainless steels in terms of durability, strength and performance.

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