In an interview on Oct. 14, Kyushu University professor Chisako Masuo said that Taiwan and Japan lack close cooperation despite generally favorable public perceptions of each other. Both sides assume they understand one another, but have made little effort to exchange views on important issues, she said.
Masuo urged the two sides to deepen mutual understanding and cooperate more closely to assess China’s intentions and protect their shared interests, particularly as Beijing expands its maritime activities east of Taiwan.
Chinese maritime patrols and other “gray zone” operations will continue and could become more sophisticated, despite growing optimism in Japan that China would not invade Taiwan, she said.
Her comments highlight a concerning disconnect: Chinese encroachment is not necessarily perceived as an immediate threat and many people appear to see little risk of a full-scale invasion of Taiwan.
However, if the threat becomes imminent, it might be too late to respond effectively.
Several factors could explain the perception that led to Masuo’s warning that low expectations of an invasion could discourage cooperation even as China expands its coercion.
Perhaps the public recognizes the threat, but has grown weary of war amid the conflict between Israel and Hamas, hostilities involving the US and Iran, and more than four years of war between Russia and Ukraine. Although Taiwan and Japan are thousands of kilometers from the Middle East, the conflicts there affect them through higher energy costs, inflation and disruptions to global shipping. A conflict in the Taiwan Strait would have even more direct consequences for Japan. The strait is a major international shipping route and Japan could be drawn into a conflict even if it sought to remain neutral.
Taiwan and Japan have extensive economic, educational and cultural ties despite lacking formal diplomatic relations. Bilateral trade last year was about US$84.85 billion, with Japan supplying Taiwan with semiconductor manufacturing equipment, materials and industrial technologies, while Taiwanese firms contribute semiconductor production and electronics expertise to Japan.
People-to-people exchanges are also extensive. About 6.73 million Taiwanese visited Japan last year, while about 1.48 million Japanese traveled to Taiwan. The two sides also cooperate on fisheries, marine science, environmental issues, and maritime search and rescue.
However, security cooperation is limited compared with the economic and societal ties. Neither side has a formal mutual-defense treaty or combined military command, and there is no publicly established program of regular bilateral combat exercises.
Nevertheless, cooperation has expanded as both sides become increasingly concerned about Chinese maritime activity and the risk of a Taiwan Strait conflict.
In July 2024, the coast guards of Taiwan and Japan conducted joint search-and-rescue and salvage drills, the first exercises of their kind since 1972. Political and defense-related contacts have also increased, including a visit to Japan by the deputy minister of national defense in April last year.
Defense-industry cooperation, particularly involving drones, has gained momentum. A report last month identified at least 20 publicly disclosed drone industry memoranda of understanding signed by the two sides since 2017. The agreements indicate growing industrial links, but do not necessarily entail joint military operations.
The expansion of security cooperation reflects shared concerns about Chinese naval and coast guard activity around Taiwan and in the East China Sea, as well as the potential consequences of a Taiwan Strait conflict for Japanese territory, shipping and regional stability. Practical cooperation allows both sides to improve communication, maritime capabilities and technological resilience without establishing a formal military alliance that could provoke Beijing.
Masuo is right that there is considerable room to deepen Taiwan-Japan ties. The question is how far that cooperation can go without provoking Beijing, and how much weight Japan should give to that risk.
Japanese Prime Minister Sanae Takaichi has said that a Taiwan contingency could constitute a situation threatening Japan’s survival and potentially justify the use of its Self-Defense Forces, a position that has drawn strong objections from Beijing.
Closer cooperation between Taipei and Tokyo would be prudent given their shared security concerns, but moving beyond rhetoric would require concrete agreements. They could create opportunities for joint training, defense research, and information and intelligence sharing. For Taiwan, building cross-party consensus on agreements with Japan could help ensure that the relationship endures regardless of what changes in domestic politics.