Making a good knife requires constant smelting: high temperature heating and repeated folding , hammer flat, especially to make the blade more sharp, use local quenching.And through the method of changing the steel structure to solve thousands of years of toughness and hardness of the difficult problem.katana has a very high technology in making method. Generally speaking, after cutting edge, quenching and polishing, it should be combined with white wood handle scabbard to keep the blade for sale, while handle, scabbard, tan and other dao are used as another line, and it is decorated by special metalworking .