Sakai Takayuki's Aonikou Series are top-rank products that ensure a wonderful sharpness and manufactured with a unique traditional method, Honkasumi. This is a sharp Japanese knife, using blue-2 steel from Yasuki, which is the highest grade of material for Japanese knife.
Honkasumi are made from two materials: high-carbon steel "hagane" (Yasuki blue-2 steel) and soft iron "jigane" forged together. This style of knife offers a similar cutting edge to a honyaki blade in high-grade knives. It offers the benefit of being "more forgiving" and generally easier to maintain than the honyaki style, at the expense of stiffness. Some see this as an advantage.
Approved craftsmen, Togashi kenji and Doi Itsuo forged it with painstaking craftsmanship and also approved craftsmen, Mr. Tosa Hrotsugi and Oda Yukinori carefully sharpened and finish up the blade. The appearance is exceptionally beautiful. You can taste joy of having a good tool like this in your hand.
It will be rusty if you do not take care of it.