The Sabun Aoko (Aogami or Blue Paper No.1) Steel Knife is made from famous Yasugi steel, known as prime high carbon steel, specifically developed for tools and knives. This one has highest wear resistance and lowest toughness. Very good steel, and very popular choice for high end Japanese kitchen knives. One of the best kitchen knife with more excellent durability of sharpness with special hardness like New Ceramic . We recommend any professional chef to use the one in their life.