 2. the first step of the train the trainer planTTT activised in March 19-20,2015,which including the diagnosis and operation hand in hand teach by Professor Yano Takeshiin,and the case discussion,and so on. Core: First, a detailed examination by white light is used to look for an irregular margin or a depressed spiny area.Then narrow-band imaging is used to look for a demarcation line, an microvascular pattern and microsurface pattern .five young endoscopist accepted the TTT plan and the other five not accepted. 