Hitachi Aoichiko Knife Steel
Composition Analysis Graph, Equivalents And Overview

Aoichiko(Hitachi) - Ref. Kitchen Knife Steel FAQ - Also referred as Ao-Ko, or Ao-ichi-ko, where ichi is one in Japanese and ko is steel. Hitachi high carbon steel(C 1.3%-1.4%), very pure(P <= 0.025%, S <= 0.004%) specifically developed for tools and knives. In my experience - it is a very good steel, and very popular choice for high end Japanese kitchen knives. A lot of Japanese custom makers use it. Takes very fine edge, and holds it long time. Easy to sharpen, even at 65HRC. Slightly better wear resistance compared to Aogami(Blue) 2, however slightly less tough compared to it. I have several kitchen knives in this steel: Watanabe Honyaki Gyuto, Nakiri and others. Takes patina easily, but just wiping it clean during cutting and washing after using it, prevents rust completely. Very easy to maintain, I get by just with steeling and stropping for weeks, and I use it a lot for a home user. Takes very fine edge and performs very well with it.

Manufacturing Technology - Ingot

Country - Japan(JP)

Known Aliases:
Hitachi - Aogami 1, Hitachi - Blue 1, Hitachi - Aoko 1