Japan-China strategic rivalry

Japan's position on Taiwan sits close to the center of its relationship with China because Taiwan lies at the edge of Japan's own southwestern island chain: a Taiwan Strait contingency would occur within reach of Japanese territory and shipping lanes. Japanese officials have at times described such a contingency as a matter engaging Japan's own security, including under the country's collective self-defense doctrine, and Japanese naval vessels have transited the Taiwan Strait. China regards Taiwan as an internal matter and treats foreign statements on it as bearing on its own sovereignty; Japanese remarks on the subject have prompted formal protests, demands for retraction, and diplomatic friction including incidents at each country's embassy. The dispute is distinct from the wider Taiwan Strait confrontation between China, Taiwan and the United States: its terrain is the bilateral Japan-China relationship, triggered by and centered on Japan's own statements and posture.

Japan's postwar constitution renounces the use of force to settle international disputes and for decades constrained its military to a strictly defensive posture. Since the 2010s, Japan has raised its defense budget, developed long-range counter-strike missile capability, eased restrictions on defense equipment exports, and debated formal revision of Article 9 -- changes officials in Tokyo describe as a response to a more severe regional security environment, including Chinese naval and air activity near Japan's southwestern islands. Chinese officials and state media describe the same changes as a departure from Japan's postwar pacifist commitments and connect them to Japan's wartime history. The debate involves Japan's Self-Defense Forces, its defense budget process, and its security relationships with the United States and other partners.

China supplies the large majority of the world's processed rare-earth minerals, an input Japanese manufacturers depend on, and has historically been Japan's largest source of inbound tourists. Both have become instruments in the bilateral relationship: Chinese export licensing on rare earths and related materials to Japan has tightened at points of diplomatic friction, Chinese authorities have issued travel advisories that preceded declines in tourist arrivals from China, and imports of Japanese seafood have at times been restricted. Japanese nationals, including company employees, have also been detained by Chinese authorities. Japanese and allied governments have responded by pursuing alternative mineral sources, including seabed extraction and recycling, and joint stockpiling arrangements with other countries.

The Senkaku Islands, a small uninhabited island group in the East China Sea, have been administered by Japan since 1972 and are also claimed by China, which calls them the Diaoyu Islands, and by Taiwan. China Coast Guard vessels regularly enter the contiguous zone and, at intervals, the territorial waters around the islands; Japan's coast guard tracks these vessels and at times acts to expel them. The dispute also extends to the wider East China Sea, where the two countries' exclusive economic zone claims overlap and where survey vessels, fishing activity and gas-field infrastructure near the median line have periodically drawn protest from Japan. The islands lie near Japan's Yonaguni and Ishigaki islands, within the broader geography of the first island chain.

Japan's conduct during its wartime occupation of parts of China, including the 1937 Nanjing Massacre, the use of forced labor, and the coercion of women into wartime brothels, remains a subject of dispute between the two countries' historical accounts. Visits or ritual offerings by Japanese officials to Yasukuni Shrine, which honors Japan's war dead including convicted war criminals, routinely draw formal protest from China. Related disputes include denial or minimization of wartime events by some Japanese public figures, the restoration of wartime military rank titles, unexploded or abandoned wartime chemical weapons still being cleared in China, and calls for Japan to return cultural relics removed during the war. These disputes recur independently of the theater's other dimensions and are raised by Chinese officials and state media at points of broader diplomatic friction.