Three Government ships of China on 5 May 2013 entered into waters of Senkaku islands, which are disputed and controlled by Tokyo. The surveillance ships of China sailed 12-nautical-mile zone off the Senkaku islands, also known as Diaoyu by China.
The government ships of China have sailed into five islands in recent past. This has led to diplomatic disputes with Japan. In April 2012, eight vessels of the Chinese Government had entered in the disputed waters.
The disputed Senkaku islands
Senkaku islands, which are also called Diaoyu Islands in China or Pinnacle Islands, are basically the group of uninhabited islands. These islands are under the control of Japan in East China Sea. These islands are located in the east of Mainland China, northeast of Taiwan, west of Okinawa Island as well as north of the southwestern end of Ryukyu Islands.
There is terrestrial sovereignty over Senkaku islands as well as maritime boundaries around these islands are disputed between China, Taiwan and Japan.
China and Taiwan claim that Senkaku islands have remained a part of China since 1534. However, in 1894-1895, Japan got the control of the islands during first Sino-Japanese War and the Treaty of Shimonoseki was signed.