The Indo-Pacific is currently facing rising threats not seen since the height of the Cold War, and Japan is at the forefront of tensions. Japan has a massive maritime shelf and archipelago to patrol and secure, which is becoming contested by adversaries in the region. Along the South China Sea and the Ryukyu and Kuril Islands, Tokyo faces major threats from rising ambitions in Beijing and an increasingly unpredictable Moscow, which has become more belligerent towards its neighbors. The Japanese Maritime Self-Defense Forces (JMSDF) are increasingly being tested on their red lines and deterrence threshold in key flashpoints, such as the East and South China Seas. To counter these threats, Japan will need to reassess its maritime security and diversify and expand its contingency planning in the increasingly tense Indo-Pacific region.

The Senkaku Islands, which are part of the Ryukyu Islands, are crucial to Japan’s security and history. While both Taiwan and China also lay claims to the Senkaku Islands, Beijing is actively trying to gain a foothold over them in the East China Sea. For the past 130 years, the Senkaku Islands have been administered or patrolled directly by Japan, as the islands were annexed in the aftermath of the First Sino-Japanese War and the subsequent Treaty of Shimonoseki. The Qing Dynasty and Kuomintang would subsequently ignore the Tokyo-led administration over the islands.

After the unconditional surrender of Imperial Japan, America would administer the islands until 1972, around the same time China began laying claims to the Senkaku Islands due to their strategic location and potential gas reserves. Furthermore, Beijing became emboldened as the U.S. government recognized the People’s Republic of China as the legitimate government of China, rather than the government of Taiwan. During Tokyo’s gridlock over expanding militarization and the U.S.-led perpetual wars in Afghanistan and Iraq, China built up its navy, the PLAN, and started flexing its muscles around the Senkaku Islands. In 2013, Beijing and Tokyo nearly intertwined into armed naval clashes with reports of Chinese maritime PLAN warships locking onto a Japanese destroyer, with Japan declaring that if militarized drones entered their Economic Exclusive Zone, it would be considered a drastic escalation.

Several collisions have taken place around the islands involving not just China, but also Taiwan, with both countries engaging in tit for tat boat incidents against Japan, which further strained relations between all three nations. Despite the claims, Taipei has become wary of Xi Jinping’s government, which prioritizes unification, either peacefully or by force, against Taiwan. Due to the threats, relations between Tokyo and Taipei have improved, which has mitigated some of the trilateral tensions.

The South China Sea is becoming a powder keg not only for the Indo-Pacific but for the entire world. Along the South China Sea are major maritime trade routes and an estimated 190 trillion cubic feet of natural gas. Due to the energy resources and potential to control the tempo of shipping lanes, Beijing is maneuvering the PLAN to establish a concrete foothold in the South China Sea. Numerous incidents have taken place in the South China Sea, which has seen the PLAN and Chinese Coast Guard involved in ramming fishing and naval vessels belonging to Vietnam and the Philippines, the latter of which holds major defense pacts with the United States.

Militarization in the South China Sea, which leads to disruptions in trade, is a key concern for Tokyo, as the Japanese economy is closely intertwined with the Luzon Strait. To counter Chinese naval aggression, Japan finalized the aforementioned defense pact, known as the Reciprocal Access Agreement (RAA), with the Philippines, which will take effect in September 2025. In the RAA, both Tokyo and Manila will allow access to each other’s forces on their territorial waters and strengthen military exercises. This reveals the truth between the two nations, as Japan is now the third country the Philippines has granted this access to, following the United States and Australia.

The Kuril Islands, historically under Japanese rule, have been traded between Japan and Russia on several occasions. The Russian Empire annexed the islands in 1855, but they were returned to Japanese hands in the aftermath of the 1905 war. The Soviet Union, a successor to the Russian Empire, captured the islands in 1945. Although then-President FDR agreed that the USSR should control the northern archipelago, the official U.S. government position differed. Instead, the Soviet possession of the Kuril Islands was meant to be used for negotiations with Tokyo.

Though Japan was forced to cede the islands during the 1951 San Francisco Treaty, the documents did not recognize full Soviet sovereignty over them. Still, the Russian Federation, one of the successors of the USSR, would continue to occupy the islands to this day. Lacking a formal treaty, the Kuril Islands dispute remains a de facto continuation of World War II, as the status was not settled through a peace treaty. Instead, Russia has militarized the islands in a show of force towards Japan. Russia has deployed various anti-air and anti-ship missiles with a range covering the maritime space of the Kurils. Furthermore, not only did Russia withdraw from negotiations and the fragile peace treaty, but Moscow also ended the longstanding visa-free program that allowed former Japanese residents of the Northern Territories to visit.

Tokyo’s regional threats are existential but can be managed through diplomatic measures, implementing stronger deterrence, strengthening alliances, and hotlines. Regarding the ongoing disputes over the Senkaku Islands, Japan, under international law, has an Economic Exclusion Zone (EEZ) around the islets, which Tokyo can use to continue asserting its sovereignty. Growing relations with Taipei can mitigate incidents, while Tokyo has a partner, it can help counter Beijing within the East China Sea and potentially the Strait of Taiwan.

Becoming more involved in safeguarding maritime shipping lanes, such as the Luzon Strait, which are crucial to the Japanese economy, will need to be at the forefront of Tokyo’s regional soft power. Furthermore, the defense pact with the Philippines, along with lobbying for more joint patrols with Western partners in the South China Sea, can help mitigate PLAN’s assertive maneuvers. Regarding the Kuril Islands, Tokyo should designate a hotline with Moscow to promote back channels in case tensions continue to escalate. With Russia’s confrontational approach, Japan is becoming increasingly entangled in supporting Ukraine’s defense and territorial sovereignty, sharing satellite data, aid, and security guarantees whenever the war ends.

The United States also supports Japan’s stance on the Northern Territories, which is similar to its position on the Senkaku Islands conflict. With Russia’s influence, soft power, and force projection capabilities waning, both Tokyo and Washington can apply further diplomatic pressure on Moscow to end the escalation over the Kuril Islands.

The Indo-Pacific is becoming a flashpoint that requires regional powers, such as Japan, to step up amid regional tensions near the Kuril Islands and the East and South China Seas. Tokyo’s increasing militarization, improved regional partnerships, and diplomatic measures will be paramount in mitigating tensions, and further focus should be on enforcing channels and hotlines to prevent potential conflicts.

Further Reading on E-International Relations

• New Book – Asian Territorial and Maritime Disputes: A Critical Introduction
• Opinion – The Impact of an Indecisive America on the Indo-Pacific
• Opinion – With the Rise of the ‘Indo-Pacific’, Has the ‘Asia-Pacific’ Faded Away?
• Opinion – Emerging Patterns of Trade in the Indo-Pacific
• Opinion – The Coming of Age of the European Union’s Indo-Pacific Strategy
• Opinion – A ‘Weakened’ Quad?