London

THERE are few economies and societies on earth more complementary than China’s and Japan’s. The Chinese are relatively young, poor and restless and fiercely committed to economic growth. The Japanese are relatively old and sated, but technologically advanced and devoted to guarding their high standard of living. Proximity would seem to make the two nations ideally suited to benefit from each other.

But Japan is afraid of China’s rise, because the Chinese economy is so much more dynamic than Japan’s. And China is troubled by Japan, because the island nation seems to act as an unsinkable American aircraft carrier just off its coast.

Over the last year, nationalists in both countries have fought a war of words over the disputed islands that Japan calls Senkaku and China calls Diaoyu. Japan’s new right-wing prime minister, Shinzo Abe, has alarmed Chinese leaders with his calls for revisiting its commitment to pacifism, enshrined in the American-imposed postwar constitution, and for making the school curriculum more patriotic.

The long shadow of history continues to haunt relations between the two countries. In Asia, World War II started in 1937 as a Sino-Japanese war; millions of Chinese were killed as a result of Japan’s expansionism. But that does not explain why young people in China and Japan today are more inimical in their views of one another than their forebears — even immediately after the war — were.