Japan is by far the most important to China of the nonsuperpower developed nations. Among the reasons for this are geographical proximity and historical and cultural ties, China's perception of Japan as a possible resurgent threat, Japan's close relations with the United States since the end of World War II, and Japan's role as the third-ranking industrialized power in the world. Japan's invasion and occupation of parts of China in the 1930s was a major component of the devastation China underwent during the "century of shame and humiliation." After 1949 Chinese relations with Japan changed several times, from hostility and an absence of contact to cordiality and extremely close cooperation in many fields. One recurring Chinese concern in Sino-Japanese relations has been the potential remilitarization of Japan.

At the time of the founding of the People's Republic, Japan was defeated and Japanese military power dismantled, but China continued to view Japan as a potential threat because of the United States presence there. The Sino-Soviet Treaty of Friendship, Alliance, and Mutual Assistance included the provision that each side would protect the other from an attack by "Japan or any state allied with it," and China undoubtedly viewed with alarm Japan's role as the principal United States base during the Korean War. At the same time, however, China in the 1950s began a policy of attempting to influence Japan through trade, "people's diplomacy," contacts with Japanese opposition political parties, and through applying pressure on Tokyo to sever ties with Taipei. Relations deteriorated in the late 1950s when Chinese pressure tactics escalated. After the Sino-Soviet break, economic necessity caused China to reconsider and revitalize trade ties with Japan.

Sino-Japanese ties declined again during the Cultural Revolution, and the decline was further exacerbated by Japan's growing strength and independence from the United States in the late 1960s. China was especially concerned that Japan might remilitarize to compensate for the reduced United States military presence in Asia brought about under President Nixon. After the beginning of Sino-American rapprochement in 1971, however, China's policy toward Japan immediately became more flexible. By 1972 Japan and China had established diplomatic relations and agreed to conclude a separate peace treaty. The negotiations for the peace treaty were protracted and, by the time it was concluded in 1978, China's preoccupation with the Soviet threat led to the inclusion of an "antihegemony" statement. In fewer than three decades, China had signed an explicitly anti-Japanese treaty with the Soviet Union and a treaty having an anti-Soviet component with Japan.

From the 1970s into the 1980s, economic relations were the centerpiece of relations between China and Japan. Japan has been China's top trading partner since the 1960s. Despite concern in the late 1980s over a trade imbalance, the volume of Sino-Japanese trade showed no sign of declining. Relations suffered a setback in 1979 and 1980, when China canceled or modified overly ambitious plans made in the7da he late 1970s to import large quantities of Japanese technology, the best-known example involving the Baoshan iron and steel complex in Shanghai. Lower expectations on both sides seemed to have created a more realistic economic and technological partnership by the late 1980s.

Chinese relations with Japan during the 1980s were generally close and cordial. Tension erupted periodically, however, over trade and technology issues, Chinese concern over potential Japanese military resurgence, and controversy regarding Japan's relations with Taiwan, especially Beijing's concern that Tokyo was pursuing a "two Chinas" policy. China joined other Asian nations in criticizing Japanese history textbooks that deemphasized past Japanese aggression, claiming that the distortion was evidence of the rise of militarism in Japan. By the late 1980s, despite occasional outbreaks of tension, the two governments held regular consultations, high-level leaders frequently exchanged visits, Chinese and Japanese military leaders had begun contacts, and many Chinese and Japanese students and tourists traveled back and forth.

Data as of July 1987