The leaders of China and Japan shook hands and spoke to each other in an unexpected meeting on the sidelines of the G20 summit.
The BBC reports President Xi Jinping and Prime Minister Shinzo Abe had not met since they took power in March 2013 and December 2012 respectively.
Ties between the two countries have been severely strained by a territorial dispute. Both claim islands in the East China Sea.
The islands, known as Senkaku in Japan and Diaoyu in China, are controlled by Japan. But China was angered last year when the Japanese government bought three of the islands.
Japanese officials said the two leaders met for between four and five minutes just before the main G20 session began at the summit in St Petersburg on Thursday.
