Relations between Asian neighbours China and Japan have rarely been harmonious.
Recent signs of rapprochement have come after almost a decade of mutual antipathy, amid territorial disputes and rows over Japan's conduct in World War II.
China has accused Japan of failing to repent for historical wrongs, while Japan accuses China of dwelling on the past.
But behind the talk of the past there are also fears and ambitions for the future.
As China's economy grows, competition with Japan for resources and markets is rising.
Both wish to match their economic prowess with leading roles in world diplomacy, and both are anxious to take maximum advantage of a rapidly changing regional power balance.
The BBC News website looks at the issues that lie behind relations between two Asian giants. Click on the links above to find out more.