Japan in 2016 planned to sail a Maritime Self-Defense Force ship into an area claimed by China as its territorial waters in the South China Sea, in response to a similar move by China in Japanese waters to the north, sources familiar with Sino-Japanese ties said Saturday.
The planned move, a Japanese equivalent of the "freedom of navigation operations" conducted by the U.S. Navy in the South China Sea, was never carried out, however, over concerns that going ahead with it would seriously harm bilateral ties, according to the diplomatic sources.
The Chinese government led by President Xi Jinping has in recent years aggressively pressed its territorial claims in regional waters, including over the Japanese-administered Senkaku Islands in the East China Sea.