Clay tempered katana are swords made according to a particular process of blade reinforcement. During the forging, there are steps to go through involving several steps and some compounds mixture, used by the entire swords forger, yet each has its own formula. The compound mixture is none but Clay recipe that each forger has a secret ingredients list. Clay tempering is supposed to be an art more than a sword works. Clay tempered katanas are said to be more resistant and durable. Clay treatment must be operated by professionals to be efficient. Also, each steel type is supposed to be responsive to different clay compositions.