In the contemporary geopolitical landscape of Southeast Asia, the rise of China represents one of the most significant shifts in regional dynamics. For Japan, a nation with profound historical, economic, and strategic interests in the region, this shift necessitates a nuanced and multidimensional strategy. This essay examines how Japan should deal with a rising China in Southeast Asia, considering historical context, economic interdependence, military strategy, and diplomatic engagement. The exploration draws upon various sources to present a comprehensive approach that balances competition and cooperation.

#### Historical Context and Strategic Interests

Historically, Japan and China have experienced periods of both conflict and collaboration. During the early 20th century, Japan’s imperial ambitions led to a confrontation with China, culminating in the Second Sino-Japanese War. Post-World War II, Japan redefined its role in Asia, focusing on economic growth and regional stability. However, the rise of China as a financial and military power has reintroduced a competitive element to this relationship.

In Southeast Asia, Japan has long been a key player. The region is vital due to its strategic maritime routes and economic potential. China’s Belt and Road Initiative (BRI) and its assertive stance in the South China Sea represent a growing challenge to Japan’s influence. According to Tsuneo Watanabe, “Japan’s grand strategy can be said to have been shaped by the pursuit of complex security and economic interests within the Japan-US-China triangle, whose history can be traced back to the 1930s” (Watanabe, 2015). Therefore, Japan’s strategy must navigate these historical and strategic complexities.

Indeed, the comprehensive historical context shapes Japan’s perspective and possible responses to China’s rise. As noted in “Report of the Expert Panel for the 50th Year of ASEAN-Japan Friendship and Cooperation,” Japan’s historical engagement in Southeast Asia dates back to several decades and includes considerable contributions to the region’s political and economic landscape. The relationship is multifaceted involving deep strategic commitments such as the Free and Open Indo-Pacific (FOIP) strategy which aims to ensure a rules-based order in the region (Ministry of Foreign Affairs, 2023).

#### Economic Interdependence

Economically, both Japan and China are deeply integrated with Southeast Asia. China’s BRI aims to enhance infrastructure connectivity and increase its influence, while Japan has historically provided significant development aid and investment to the region. Given this economic interdependence, Japan should adopt a complementary rather than confrontational economic strategy toward China.

For instance, Japanese companies can collaborate with Southeast Asian nations on infrastructure projects not exclusively tied to Chinese funding. By providing alternatives, Japan can help these nations avoid excessive reliance on China. Stephen R. Nagy notes that Japan’s “reputation became one of being an essential partner to the region and Tokyo began to see itself as having the responsibility to contribute to the region’s development as part of its national interests” (Nagy, 2024).

Moreover, Japan can leverage its technological expertise in sectors such as renewable energy, healthcare, and digital infrastructure. By positioning itself as a leader in these fields, Japan can enhance its soft power and economic influence in Southeast Asia, balancing China’s footprint. As Hoang Thi Ha states, “Japan’s active participation, support, and leadership in various multilateral economic partnership agreements…will remain pivotal, especially as the US is turning away from the global multilateral trading system, amidst a backdrop of rising unilateralism and protectionism worldwide” (Hoang, 2024).

In exploring how economic strategies play out in the South China Sea, Hidetaka Yoshimatsu explains, “While China has employed economic means as ‘carrot and stick’ to influence the position of Southeast Asian states, Japan has intensified economic aid, even revising the basic principles of its development assistance policy” (Yoshimatsu, 2017, p. 295). This strategic use of economic measures is crucial for understanding Japan’s approach to balancing economic interdependence with strategic interests.

#### Military Strategy and Security Partnerships

In terms of military strategy, Japan faces a delicate balancing act. While it is crucial to deter potential aggression and ensure regional security, overt military expansion could provoke an arms race. Thus, Japan should focus on building robust security partnerships with Southeast Asian nations.

Japan’s Self-Defense Forces (JSDF) can engage in joint exercises, capacity-building initiatives, and disaster relief operations with Southeast Asian militaries. Such cooperation fosters mutual trust and enhances regional stability. According to Japan’s Ministry of Foreign Affairs, "Japan will strengthen cooperation in the field of maritime security based on the rule of law and achieving a free and open Indo-Pacific” (MOFA, 2022).

Additionally, Japan can support regional institutions such as the Association of Southeast Asian Nations (ASEAN) Defense Ministers’ Meeting (ADMM-Plus) and the ASEAN Regional Forum (ARF). These platforms enable collective dialogue and collaboration on security issues, providing a counterbalance to China’s unilateral actions in the South China Sea. Hoang Thi Ha emphasizes that "Japan’s steadfast commitment to adhere to its pacifist principles” underlines its approach to security cooperation, prioritizing non-traditional security challenges (Hoang, 2024).

Hidetaka Yoshimatsu highlights Japan’s strategic use of economic aid to fortify its defense relationships: “Japan has utilized foreign economic aid for strategic objectives, even revising the basic principles of its development assistance policy” (Yoshimatsu, 2017, p. 295). This underscores how economic and security strategies intersect in Japan’s approach to regional stability.

#### Diplomatic Engagement and Multilateralism

Diplomatically, Japan’s approach should prioritize multilateralism and adherence to international norms. Promoting a rules-based order in Southeast Asia aligns with Japan’s national interests and resonates with the region’s smaller nations, which often feel vulnerable to larger powers.

According to Japan’s Ministry of Foreign Affairs, the Free and Open Indo-Pacific Strategy (FOIP) emphasizes "the promotion and establishment of the rule of law, freedom of navigation, and free trade” (MOFA, 2022). By engaging countries through this strategy, Japan can present itself as a reliable and principled partner, contrasting with China’s sometimes coercive diplomacy.

Furthermore, Japan should actively participate in regional economic forums such as the Regional Comprehensive Economic Partnership (RCEP) and the Comprehensive and Progressive Agreement for Trans-Pacific Partnership (CPTPP). These platforms not only facilitate economic integration but also serve as venues for promoting shared values and norms.

Michael J. Green underscores that Japan’s FOIP “flows from a strategic worldview in Japan, even if it does not spell out every detail of the national objectives and instruments of power to be employed” (Green, 2018). By adopting this framework, Japan emphasizes “rule-of-law; transparency; openness; high-quality rules for trade, investment and infrastructure; and the prevention of coercive actions against smaller states” (Green, 2018).

According to Yoshimatsu, Japan’s strategy in multilateral settings includes expanding the scope from “maritime safety to maritime security targeting China” (Yoshimatsu, 2017, p. 295). This shift in focus demonstrates Japan’s commitment to a comprehensive and multifaceted approach to regional security.