Hitachi Metals Ltd. is one of top manufactures of high grade metal products and materials, electoronics devices, high grade functional components and equipment. The company is well known as a manufacture of its “Yasuki Hagane” YSS (Yasuki Speciality Steel) for cutlery industries.
Yasuki Hagane steel has been produced in their plant in Shimane prefecture in Japan where the high quality iron sand has been produced for making traditional Japanese swords since ancient times. These are three main premium grade high carbon steels (Shirogami, Aogami and Aogami Super) that have been used for making Japanese made field & kitchen knives. Hitachi metal is also known as the manufacture of high grade premium stainless steel, ATS-34 and ZDP-189.
ZDP-189 is the highest performing steel in the knife industry today.
White Steel (Shirogami)
This is refined carbon steel that does not contain any ingredients and can be used for making high-grade Hocho (Japanese kitchen knives), hatchets, axes, sickles and chisels.
Blue Steel (Aogami)
This is made by adding chromium and tungsten to Shirogami (White Steel) that makes the material more durable and provides corrosion resistance and mostly used for making high-grade Hocho (kitchen knives) and outdoor knives.
Super Blue Steel (Aogami Super)
This is the highest grade steel in their product line that contains high percentage of carbon, chrome to increease hardness, improviding edge retention and corrosion resistance.
Cowry-Y is a powdered metallurgical steel produced by Daido Steel in Japan and it not available in the United States. This steel is capable of a higher hardness without being brittle. The resulting edge has extremely good edge retention and can get better finish if you prefer mirror finish on your knife blade. Cowry-Y contains 1.25 of Carbon, 14.5 of Chromium, 3.0 of Molybdenum, 1.0 of Vanadium, 0.3 Nb in HRC62-64.