Japan’s stance on the Taiwan Strait

Author: Masaya Inoue, Keio University

Tensions are rising in the Taiwan Strait. In recent years, many developed nations have become concerned over China’s military expansion. The Russian invasion of Ukraine in February 2022 has increased anxiety that China, with its military dominance, will unilaterally attempt to change the status quo in Taiwan.

In June 2022, the Leaders’ Communique issued at the G7 Summit included a statement to ‘underscore the importance of peace and stability across the Taiwan Strait and encourage a peaceful resolution of cross-Strait issues’. This is the second consecutive year that Taiwan has been mentioned.

Among G7 members, Japan and the United States stand out as having strong stances towards defending Taiwan. At the April 2021 Japan–US Leaders’ Summit, the joint statement reiterated ‘the importance of peace and stability across the Taiwan Strait’ and encouraged ‘the peaceful resolution of cross-Strait issues’. It was the first time that Taiwan was mentioned in a Japan–US joint leaders’ statement since 1969.

Japan’s stance on Taiwan has been ambiguous for many years. This is the result of complex internal politics rather than strategic ambiguity. Taiwan is a sensitive issue in Japan’s relations with both the United States and China. Within the ruling Liberal Democratic Party, pro-Taiwan and pro-China factions are fiercely opposed. Because Japan’s participation in a potential conflict over Taiwan is affected by the Japanese constitution — which has strictly constrained the use of military force overseas — Japan’s involvement has become a point of contention among conservative and reformist forces.

The ‘Taiwan Clause’ included in the 1969 Japan–US Joint Statement meant that if a conflict occurred over Taiwan, the Japanese government would guarantee the deployment of US military personnel stationed in Japan.

In exchange for the United States promise to return Okinawa, Japan expressed its position that a conflict over Taiwan was not disconnected from its domestic security. The inclusion of the phrase that ‘the maintenance of peace and security in the Taiwan area was also a most important factor for the security of Japan’ was a last-minute expression thought up by the Japanese government, seeking to avoid excessively provoking China.

While upholding the legal force of the ‘Taiwan Clause’, Japan has tried to deal with the Taiwan problem politically with China. In the Joint Communique of the Government of Japan and the Republic of China in 1972, China stated that ‘Taiwan is an inalienable part of Chinese territory’. Japan displayed ‘understanding’ and ‘respect’ and showed China political compromise by stating that it ‘firmly maintains its stand under Article 8 of the Potsdam Proclamation’, which referenced the return of Taiwan to China. At the time the Japanese government accepted the Potsdam Declaration, ‘China’ meant the Republic of China. However, the Japanese government has used the term to refer to the People’s Republic of China since 1949.

The Japanese government’s position was that it respected the ‘One China’ policy and aimed for a peaceful resolution of any future separation of China and Taiwan, but reserved the option to apply the US–Japan Security Treaty if conflict erupted. The thinking of the Japanese government at that time has formed the basis of government opinions up until today.

Japan has continued to adopt a politically ambiguous position on whether a conflict over Taiwan is included in the application of the US–Japan Security Treaty. In September 1997, the guidelines underpinning Japan–US security cooperation were reconsidered and legal preparations were made to enable the Japan Self-Defense Force to support the US military in the event of ‘situations in areas surrounding Japan that have important influence on Japanese security’. But the government at the time avoided clarifying whether the Taiwan Strait was included in the ‘areas surrounding Japan’.

In the 2010s, as Chinese military dominance gained momentum, former prime minister Shinzo Abe responded strategically to this situation. But when Abe passed a range of peace and security laws in 2015, he was cautious in his comments concerning a possible conflict over Taiwan.

The purpose of Abe’s peace and security laws was to enable the partial exercise of collective self-defence, which had been difficult to engage in under previous interpretations of the Japanese constitution. Even debates in the National Diet had avoided commenting on situations where it would be possible to exercise collective self-defence. The government at the time repeatedly said that it would determine such circumstances concretely and on a case-by-case basis when a military attack occurred.

Against the backdrop of US–China tensions, and with growing Chinese military intimidation, the Japanese government shifted its position of ambiguity and started to make clear that it would participate in the defence of Taiwan. As the Japanese public became increasingly concerned about the threat posed by China, the Japanese government came to believe that a positive stance on the Taiwan issue would be supported by public opinion. Abe joined an online symposium held in Taiwan in December 2021, where he stated that ‘a Taiwan crisis is a Japan crisis; it is also a crisis for the Japan–US alliance’. As the Japan–China relationship has continued to cool, pro-China groups within Japan have lost their influence, while calls for Japan to send a clear message regarding the defence of Taiwan have become stronger.

The tone of the debate in Japan continues to evolve. Yet, unlike Abe’s remark, a Taiwan crisis will not necessarily lead to a crisis for Japan directly. Joint strategic plans to prepare for conflict over Taiwan are being advanced at the operational level, but what is more important are the decisions at the government level.

If a conflict occurs in the Taiwan Strait, it is the Japanese government which will decide whether to commit to supporting the US military or to engage in joint strategies with the US military by exercising collective self-defence. The authorisation of the Diet is also necessary to facilitate these decisions. As to whether Japan should bear the risk of getting tangled up in a war with China to defend Taiwan, the government does not yet have the support of the Japanese people.

It is highly likely that any conflict over Taiwan would be a hybrid war that combines tactics like guerrilla espionage and cyber-attacks. Unless the Chinese military directly attacks the US military bases in Okinawa or the Sakishima Islands, the grey area of the present circumstances has so far staved off war. Japanese politicians will eventually be pressured to make the difficult decision of determining at what stage the situation should be considered an ‘emergency’.

The Japanese government should not soften its position in favour of a peaceful resolution to the Taiwan problem through diplomacy. But at the same time, as a conflict over Taiwan — the worst possible scenario — becomes more realistic, public debate about the extent of a military response will be necessary.

Masaya Inoue is Professor of Political Science in the Faculty of Law at Keio University.

This article appears in the most recent edition of East Asia Forum Quarterly, ‘Japan’s strategic choices’, Vol 14, No 3.