Taipei and Tokyo have long enjoyed warm relations that are cultural, political and economic — but these ties must now be deepened and expanded to meet regional threats.
The Taiwan Strait is not the only hotspot in the region. Indeed, East Asia has become a theater of growing tensions, which have led to a revitalization of Japan’s Self-Defense Forces (JSDF) and a shift in Japan’s civil-military relations.
Once cautious to avoid provoking Beijing, Tokyo now increasingly sees Taiwan’s fate as central to its own security. A conflict in the strait would have immediate spillover effects on the Japanese archipelago, giving China a strategic position to advance its claims on the Senkaku Islands.
Behind the scenes, Japanese policymakers and military command are recalibrating national defense strategies. The era of strategic ambiguity is giving way to a new realism, one in which Japan’s remilitarization could prove pivotal in sustaining peace and deterring conflict in the region.
Beyond security, Japan’s diplomatic backing is just as vital. By supporting Taiwan’s participation in international organizations and expanding its global ties, Tokyo helps anchor Taiwan in the international community, bolstering peace and stability across the region.
In this context, Taipei and Tokyo must work together to deepen both their security cooperation and diplomatic engagement by strengthening mutual resilience, reinforcing the regional status quo, and advancing lasting peace across East Asia.
Japan’s growing military
Since the early 1990s, Japan Self-Defense Forces have gradually returned to the center of the national security strategy, pushed by both political decisions and security imperatives. Article 9 of the constitution, which prohibits war, was reinterpreted in 2014, while the most recent National Security Strategy demonstrates Japan’s determination to build an effective regional deterrent posture.
While this military shift can be explained by domestic factors, external threats remain central to this transformation. China, alongside North Korea, is particularly viewed as a major menace to Japan’s national security.
Tokyo and Beijing have a long-standing territorial dispute over the Senkaku Islands. Since 2010, China has grown increasingly assertive and regularly entered into Japan’s contiguous zone and territorial sea.
Taipei and Tokyo share a common security environment: should Taiwan fall into China’s hands, the People’s Liberation Army would gain free access to the East China Sea, threatening Japan’s numerous remote islands far from Honshu.
Taiwan embodies a shield for Okinawa and the Senkaku Islands. Equally important, in a Taiwan contingency scenario, the PLA would certainly intervene in Japan’s water and airspace, risking confrontation and disrupting shipping routes on which Japan deeply relies.
Taipei needs Tokyo. Tokyo needs Taipei. Yet, the lack of military collaboration between the two nations is a visible vulnerability for both.
However, developments still exist. On Sept. 25, 2024, a Japanese destroyer sailed through the Taiwan Strait for the first time since the establishment of the Japan Maritime Self-Defense Forces in 1954, sending a clear signal to Beijing. The recent establishment of Japan’s Joint Operations Command to enhance rapid responses for national security threats may be closely linked with the situation in the Taiwan Strait.
Additionally, in a notable development, Taiwan recently named Shigeru Iwasaki, former chief of staff of the JSDF between 2012 and 2014, as a consultant to Taiwan’s Cabinet. Iwasaki was key to advancing joint operations for the Japanese military and enhancing coordination with the US armed forces.
JSDF differs from international military standards, and therefore Japan’s goal is to increase the costs of aggression without unnecessarily triggering a confrontation with China. Intelligence sharing and coast guard cooperation are actions that could be pursued with national security in mind, while not crossing China’s red lines.
In light of these converging interests and rising threats, it is imperative that Tokyo and Taipei move beyond informal ties and pursue broader, more institutionalized security cooperation. Only by deepening their strategic partnership can Japan and Taiwan hope to ensure peace and stability across the region.
Taiwan’s place in world
Security efforts should be complemented by diplomatic support as deterrence also depends on reinforcing Taipei’s place in the international community. In this regard, Taiwan’s accession to the Comprehensive and Progressive Agreement for Trans-Pacific Partnership (CPTPP) would raise the cost of a Chinese invasion.
Japan has, since Taiwan's application in 2021, supported Taiwan’s accession to the CPTTP. This would help mitigate one of China’s biggest levers over Japan –– its economic coercive power. Diversifying trading partners and reinforcing economic stability in the Asia-Pacific would benefit Japan’s deterrence posture and support Taiwan’s broader involvement in the region.
This would also send a clear message to China: Taiwan is central for the international community and, while respecting the “one-China policy,” we will not oppose a unilateral veto over the decisions of sovereign countries.
Japan’s diplomatic support for Taiwan has also passed through Tokyo’s alignment with Taipei’s growing influence in Central and Eastern Europe, and by endorsing a bolder language regarding the necessity for peace in the strait during its G7 presidency. These developments are complemented by official visits, further promoting political exchanges between the two nations.
The Japan-Taiwan relationship is growing; the geopolitical context fosters deeper ties, and more meaningful and effective collaboration should be pursued for long-term benefits.
The time is now
Momentum is strong as diplomatic engagement is continuously growing between the two nations. Deputy Foreign Minister Wu Chih-chung (吳志中) stated that, through unofficial meetings, diplomats and officials from Japan and Taiwan are increasingly engaging with each other.
Taiwan’s recent decision to lift remaining import restrictions imposed after Fukushima’s accident testifies to how bilateral ties have kept improving.
Deeper diplomatic ties could be backed by the Japanese, who mostly view Taiwan as an independent country and would positively welcome the establishment of formal diplomatic relations between Tokyo and Taipei. Tourism plays a central role in cultural exchanges, and reinforcing it will certainly create stronger ties between the two societies.
While sudden changes in Japan’s approach to Taiwan are not to be expected in the near future, there is a clear need for a more coherent and strategic relationship between Tokyo and Taipei. What solution could be both deterrent and tailored?
I believe that a Japanese version of the Taiwan Relations Act (TRA) would be relevant, as it would enable Japan to enshrine its policy toward Taiwan in a coherent and highly symbolic law. It would integrate Taiwan into its defense strategy, and send a clear signal regarding the necessity to safeguard peace in the East Asia region.
The TRA goes beyond arms sales, embodying the basis of Taipei-Washington cooperation. A Japanese version would establish a clear legislative framework to promote economic, cultural, political, and security cooperation between the two Asian nations.
Such a policy will be hard to achieve, especially given the current political landscape in Japan. However, it should not limit Tokyo’s willingness to pursue a coherent policy toward Taiwan..
Such a decision would definitely face retaliation from China. Therefore Japan’s efforts should be backed and reinforced by other allies in the region –– notably the United States, South Korea and Australia –– who would also benefit from a closer collaboration with Taiwan.
We are currently facing an increasingly assertive China and less compliant Japan. While constitutional limitations, Japan’s economy relying on China’s market, and political instability are not making such cooperation a likely scenario in the near future, Tokyo remains, caught in a deterrence-entrapment dilemma.
It is compelled to deter China from challenging the status quo, while risking being dragged into a conflict in the strait. The need for a coherent cross-strait policy that safeguards Tokyo’s national security is urgent.
In the short term, Sunday’s election within Japan’s ruling Liberal Democratic Party could prove to be critical for Japan-Taiwan relations. Former Japan Prime Minister Abe Shinzo’s faction, which had been a catalyst for improving the Taipei-Tokyo axis, no longer exists.
Sanae Takaichi, one of the main candidates, has been vocal against any unilateral changes in the strait and has urged Taiwan-Japan defense cooperation. Her election could enhance future ties.
Both nations really need to support each other. As Abe declared, “a Taiwan contingency is a Japan contingency,” and this requires decisive action to preserve peace in Taiwan, Japan, and the Asia-Pacific region.
