The Japanese government lodged a protest with the Chinese Embassy in Tokyo on Monday after three Chinese ships entered what Tokyo says are its territorial waters near a group of disputedislets in the East China Sea.The three Chinese coast guard vessels were spotted near the Japanese-administered Senkaku Islands around 9 am (0000 GMT) and stayed there for about two hours, the Japan Coast Guard said. The islets are also claimed by China and Taiwan, where they are known as Diaoyu and Tiaoyutai, respectively.In late November, China established an Air Defence Identification Zone (ADIZ) that covers the islets. The move was criticized by Japan, the United States and South Korea.Aircraft flying into another country’s ADIZ are required to identify themselves and provide flight data.In September 2012, Japan’s purchase of three of the islets set off anti-Japan protests in dozens of Chinese cities and a boycott of Japanese products.