The Mioroshi is a filet knife. It is thinner, lighter and longer than the deba. It can be used more efficiently than the deba because of the thinner and lighter blade. But it should not be used as a butcher knife or to cut through thick bones. Kasumi means mist in Japanese. The border of the blade on a Kasumi has beautiful waves that look like a mist. It is made of two materials; blue or white steel and soft iron. The waves are the border of hard steel and soft iron. When hard steel is covered with soft iron, it becomes less fragile. Kasumi knives are easier to maintain than Honyaki knives. Whetstone is recommended for sharpening. Not Stainless Steel*History- Since 1550, Yoshihiro, Masamune, and Yoshimitsu were known as the best sword craftsmen in Japan. After his death, Yoshihiro's apprentices continued to use his technique and traditional skills. The techniques used to make samurai swords are used to make Yoshihiro chef knives. Yoshihiro knives are now recognized to be one of the best chef knives in Japan due to the rich history and techniques that are applied from sword making to chef knives.