Beyond a doubt, one of the most delicate relationships in Asia and the world is between China and Japan.

Both are economic giants, both have large populations, their systems of government are very different and they have fought fiercely in the past. In World War II, the third war between them, Japan occupied China, killing hundreds of thousands of Chinese.

Hu Jintao just paid a five-day visit to Japan, the first for a Chinese president in 10 years. Mr. Hu's mission comes in the context of China seeking good relations with its neighbors on the eve of the Olympic games. It has also taken place as China seeks understanding for its position on Tibet.

Some ugly history between China and Japan still echoes from a dark and bloody past. The Beijing government's view, taught in its schools, is that Japan treated China with brutality in their 20th century conflict. Although Japan's leadership has expressed regret, many Chinese do not believe Japan has been sufficiently apologetic.

Japan has not helped by teaching in schools a sanitized version that -- in Chinese eyes -- does not let students understand what actually happened. The difficult part for the Japanese is that the Chinese expect Japan's leaders not to go to the famous Yasukuni Shinto shrine in Tokyo to pay respects to Japan's war dead, who include military figures convicted of war crimes. Many Japanese see visits to Yasukuni as a religious and personal matter, and not the affair of the Chinese. To go or not to go has also become a political issue among Japanese politicians.

As to the public parts of the recent visit, both Mr. Hu and Japanese Prime Minister Yasuo Fukuda stuck to the script, favoring China and Japan as partners, not rivals. Consistent with Japan's status as China's third-largest customer and its largest source of imports, and China's status as Japan's second-largest customer and largest provider of imports, the leaders had plenty to discuss on trade and investment. One point of difference was an underwater natural gas field in the East China Sea. A nice gesture was China's decision to loan Japan a pair of giant pandas, replacing one which died recently of old age.

The visit by Mr. Hu to Japan was undoubtedly useful as an ice-breaker. A lot of attitude change still needs to take place, starting in both countries' schools. America cannot be opposed to better Chinese-Japanese relations, even though that probably means both countries' relations with the United States will become less important.