The United States and Japan have begun large scale military exercises, close to waters where China and Japan are locked in a territorial dispute over a group of uninhabited islands.
More than 45,000 Japanese and American personnel are taking part on Monday.
Originally these war games were supposed to have seen US and Japanese troops carrying out a mock invasion of an uninhabited island off the south coast of Japan.
In the end, either the Japanese or the Americans decided that was a bit too provocative to China and decided to call the operation off, the BBC reports.
But the main war games on and around the island of Okinawa are still going ahead, less than 400km from the uninhabited islands.