The Great Mekong Subregion is a region in Southeast Asia that is crossed by the Mekong River. This region includes Myanmar, Vietnam, Laos, and Cambodia. China has a different concept, namely by adding the provinces of Yunnan and Guangxi as part of the Mekong. The Mekong region is very strategic in various sectors, including the economy. That is why the Mekong region (formerly Indochina) became a place of battle between countries on the pretext of utilizing various sectors in it. Now, the Mekong region is being fought over between China and Japan to expand their influence with various interests.
Japan’s defeat in World War II changed the geopolitical conditions in East Asia, including the Indochina region. Japan’s orientation is no longer on military aspects but on non-military aspects such as the economy and development. Japan must carry out economic expansion as much as possible to have a big influence on the Asian mainland. Japan is aware that its limitations in the military and security sectors are its biggest weaknesses amidst the rise of China as an economic center in Asia. Even Japan’s economic position was surpassed by China in 2010. Therefore, Japan’s interests in the Mekong region are one of the initiatives to balance China’s massive rise.
Japan’s interests in the Mekong countries are only economic interests. However, this is not easy because Japan must reconstruct and change the negative labels embedded in Japan from past colonization. Japan must construct its identity as a “good neighbor,” including all Mekong countries. One of the most famous doctrines in Japanese diplomacy is the Fukuda Doctrine. Precisely in 1977, Prime Minister Fukuda emphasized three important points in relations with Southeast Asia, namely, Japan will be free from military power, Japan will prioritize deeper relations (heart to heart), and Japan will take an active role in supporting the ASEAN region, including bilateral relations with communist/non-communist countries in it.
The Fukuda Doctrine is the cardinal principle of Japan with countries in the Mekong region. Japan’s crucial steps continued with the success of the peace initiative in Cambodia over the Vietnamese invasion. This is a manifestation of the Fukuda Doctrine, where Japan will play an active role in the progress of the Mekong region. Since then, Japan has been actively cooperating with countries in the Mekong region. In 1993, Japan proposed the establishment of the Forum for Comprehensive Development of Indochina and successfully held its first meeting in February 2025. Not only that, Japan also formed the JAPAN-ASEAN Commemorative Summit Meeting in 2003 and instilled the concept of Mekong cooperation based on Japan’s vision in the region.
Until 2009, Japan attempted to form a new institution, namely the Japan-Mekong Summit, as a formal forum between Japan and countries in the Mekong region. Japan disbursed at least 600 billion yen in aid for the Mekong region. This Japan-Mekong cooperation is based on three pillars, namely, increasing connectivity in the Mekong region, minimizing inequality between countries in the region, and increasing human and environmental security (including disaster relief).
Japan’s foreign relations with the Mekong countries have been established for a long time, even since the ancient kingdom era. For example, with Cambodia, Japan has a very close relationship, especially in terms of economic development. One of the main focuses of Japanese diplomacy is to support infrastructure development in Cambodia, such as roads, ports, and clean water facilities. In addition, Japan also provides support for the agricultural sector by helping to improve the efficiency and technology of agriculture in Cambodia. However, not only the economy but also Japan supports democratization efforts and the advancement of human rights in Cambodia. Japan tends to use a soft approach, prioritizing dialogue and cooperation, without pressuring the country. Japan also plays a role in helping to strengthen political stability in Cambodia, one of which is through assistance in government reform and the justice sector.
Laos, a landlocked country, is an important focus for Japan, especially in improving regional connectivity. Japan helps Laos by building important transportation projects such as highways and railways and providing more environmentally friendly energy facilities. In addition, Japan also contributes to education and human resource development in Laos. Japan’s diplomacy with Laos also places great emphasis on the agricultural sector to help increase more efficient agricultural production and processing. Japan supports Laos in the process of economic integration into ASEAN and is committed to helping the country face various development challenges.
Japan’s diplomacy with Myanmar is more complicated, given the unstable political situation, especially after the military coup in 2021. Nevertheless, Japan continues to maintain relations with Myanmar, but with a more cautious and considered approach. Japan focuses on providing humanitarian assistance and supporting peace and reconciliation efforts in Myanmar. Japan is also active in international dialogue, trying to find a diplomatic solution to the political crisis in Myanmar. Japan continues to support democracy, although it does not isolate Myanmar completely. The main focus of Japanese diplomacy in Myanmar is infrastructure development and the energy sector, although political challenges make economic diplomacy more difficult.
Japan and Thailand have strong relations, both in the economic and security sectors. Japan has many investments in Thailand, especially in the automotive, electronics, and manufacturing sectors. Japan’s diplomatic strategy with Thailand focuses more on deepening economic and trade relations, as well as enhancing cooperation in the field of technology. In addition, Japan also cooperates with Thailand in terms of security, especially related to regional security issues, such as maritime security and counter-terrorism. Japan supports the modernization of the Thai military through training and the transfer of technology. Japan and Thailand also strengthen cultural relations through various cultural exchange programs that enrich mutual understanding between people.
Vietnam is Japan’s main strategic partner in the Mekong region. Japan has very close economic relations with Vietnam, especially in the investment and trade sectors. Japan is one of the largest investors in Vietnam, especially in the manufacturing, infrastructure, and technology sectors. Japan is also involved in financing major projects in Vietnam, such as toll roads, ports, and renewable energy. Japan and Vietnam share the same values in terms of regional peace and stability, especially in facing maritime security challenges in the South China Sea. Japan also supports Vietnam in strengthening its military capacity and enhancing defense relations. In addition, Japan plays an important role in developing the education sector in Vietnam, especially through training a more skilled workforce.
Japan’s success in strengthening relations with the Mekong countries is inseparable from its diplomatic strategy. Japan has changed in its diplomacy with other countries by instilling a “good neighbor” image. For example, Japan is very active in providing financial assistance to the Mekong countries. This assistance is sent in the form of Official Development Assistance (ODA). Of course, ODA is not something that just comes, but there are expectations and plans behind it. This is one of Japan’s diplomatic strategies to gain support from the Mekong countries in carrying out the agenda to secure a permanent seat on the UN Security Council. However, the main thing that Japan wants most is to increase its bargaining power in the East Asia and Pacific regions amid the rise of China and the threat of North Korea’s nuclear weapons.
