Japan’s postwar diplomacy in Southeast Asia primarily aimed to secure economic interests, including resource supply areas and commodity markets, by leveraging reparations, i.e. using financial compensation and aid to build relationships and strengthen its economic presence in the region.

Since the 1960s, however, Japan’s Southeast Asian diplomacy has focused on regional political and economic stability through the expansion of economic cooperation. As the Vietnam War intensified, Japan’s vision of regional economic development indirectly supported the US strategy of stabilising the region.

However, Japan’s economic cooperation sparked wariness among Southeast Asia. First, Japanese economic cooperation led to collusion between Japanese companies and the privileged classes of the recipient countries, creating a breeding ground for corruption.

Second, most of Japan’s aid was in the form of “tied” loans that could only be used to purchase Japanese goods. Third, Japan’s rapid economic expansion in Southeast Asia through aid aroused vigilance against Japan in the region. Prime Minister Kakuei Tanaka, who visited Southeast Asia in 1974, faced violent anti-Japanese riots in Indonesia.

This incident prompted the Japanese government to rethink its Southeast Asian policy. Since then, Japan has sought to shift from a policy centred on economic cooperation, which led to Japan being seen as an “economic animal”, to a policy of playing a political role in the stability of the region.

In August 1977, Prime Minister Takeo Fukuda visited Southeast Asia and announced the “Fukuda Doctrine”. The contents of the doctrine were (1) Japan rejects the role of a military power; (2) Japan will consolidate the relationship of mutual trust and confidence based on “heart-to-heart” understanding with these countries; and (3) Japan will be an equal partner of ASEAN and its member countries, thus contributing to the building of peace and prosperity throughout Southeast Asia.

However, Fukuda showed a generous attitude toward economic cooperation, such as announcing to ASEAN leaders a policy of doubling the official development assistance (ODA) programme. As Indochina became a communist society and the US presence in Southeast Asia declined, Japan was the country that ASEAN could rely on. In fact, after the announcement of the Fukuda Doctrine, Japan’s economic relations with ASEAN countries continued to deepen.

In the ten years from 1977 to 1987, Japan-ASEAN trade increased from US$15.7 billion to US$35.1 billion, direct investment from US$600 million to US$1.5 billion, and ODA from US$270 million to US$1.68 billion, more than sixfold.

In addition, the rapid appreciation of the yen after the Plaza Accord in 1985 dealt a severe blow to Japan’s export industry, and Japanese companies took the opportunity to relocate their production bases overseas, mainly to Southeast Asia.

As a result, Japan and Southeast Asian countries changed from their previous vertical economic relations to horizontal economic relations in which the same industrial products were exchanged, accelerating Asia’s soaring economic development.

The Asian currency crisis resulting from the collapse of the Thai baht in 1997 dealt a severe blow to the economies of East and Southeast Asia. Japan actively provided economic assistance to these ASEAN countries, including the New Miyazawa Initiative, which totaled more than US$30 billion.

In addition, Japan led the Chiang Mai Initiative to prepare for future financial crises. Prime Minister Keizo Obuchi’s successive announcements of support measures were praised by ASEAN as the “Obuchi Initiative” and strengthened Japan’s presence.

However, this was the end of a significant Japanese diplomatic presence in Southeast Asia. In the 1990s, China’s economy grew rapidly, quadrupling in size, and this led to a more aggressive foreign policy. China decided to enter into a free trade agreement with ASEAN in 2002.

In response to China’s aggressive stance, Japan sought to make a comeback by concluding economic partnership agreements (EPAs) with ASEAN countries, which included investment and the movement of people.

Since 2000, however, Japan-ASEAN relations have weakened as China-ASEAN relations have become closer. Japan’s diplomacy toward ASEAN has shifted to a defensive posture against China’s growing influence in ASEAN, while in response to China’s maritime expansion, Japan’s foreign ministry has revised its previous policy of avoiding military contributions to the region and will now promote maritime capacity building in Southeast Asian countries through the “strategic use of ODA”.

Indeed, the Joint Vision Statement released at the Commemorative Summit for the 50th Anniversary of ASEAN-Japan Friendship and Cooperation in December 2023 put a “free and open Indo-Pacific” and “democracy and human rights” at the forefront, signalling being conscious of China while avoiding naming it.

Japan also announced that it would provide rescue boats and surveillance drones to Malaysia as Official Security Assistance (OSA). It also agreed with Indonesia to provide a large patrol vessel through ODA. In the context of intensifying competition between the great powers of the US and China, Japan’s current diplomacy puts Southeast Asia diplomacy in a key position.

But ASEAN countries do not want to take sides with the US or China. They want to reduce the risk of being drawn into the hegemony and alliance politics of the great powers and maintain ASEAN unity. If Japan were to force the ASEAN countries to choose between China and Japan by bringing values into the equation, they would probably be reluctant to cooperate with Japan.

The key to the future development of Japan-ASEAN diplomacy lies in giving full consideration to ASEAN’s perspective and clearly demonstrating a true sense of “equal partnership” in Japan’s diplomacy, to keep striving with ASEAN countries for overall peace and stability in the region.