A Steel Release technique in which the user turns a part of their body into greyish-black living steel. Not only does this make that portion of the body virtually impervious to harm, but it can also be used to greatly enhance the damage of the user's strikes. This is considered part of a coming of age rite within the Kurogane Clan; a clansman is considered an adult when they use the technique to block the strike of a blade in combat. A sufficiently powerful user can even turn their entire body into a steel-like armor, although it is extremely (re: nigh-prohibitively) taxing on the user's chakra.