Ohishi stainless clad aogami super knives are forged with a hard carbon steel center and a softer stainless cladding. Aogami super, or super blue steel, is a steel made by Hitachi which is formulated for long edge life. These aogami super knives hold their peak sharpness a long time and cut aggressively as they dull; where other steels become rounded as they dull aogami super maintains an agressive edge.
Ohishi aogami series are factory forged and hand ground, the face of the blade has a slight convexity which reduces sticking and friction during cutting and facilitates easy thinning of the sides later in the life of the knife as it gets sharpened into the thicker center of the knife.
Aogami super is not stainless and must be dried immediatly after use, it will get dark patina with use but any orange rust should be removed with a light abrasive.