The Senkaku/Diaoyu Islands Dispute Between Japan and China
by Afridi Ahmed
History, Competing Sovereignty & Security Dynamics
The Senkaku/Diaoyu islands, which China calls Diaoyu Dao, Taiwan refers to as the Diaoyutai islands (釣釣魚臺列嶼), and Japan administers as the Senkaku islands, are disputed territory and a flashpoint for regional tensions owing to history, sovereignty issues, strategic location, and natural resources. The dispute concerns a group of five islands with three rocky outcrops in the East China Sea (ECS). The different names used for the same group of islands by China, Japan and Taiwan are rooted in contentious history and sovereignty issues, reflecting differing national narratives and political positions.
They include five large islands: Uotsurijima (the largest), Kitakojima, Minamikojima, Kuba, and Taisho, and three rocky outcrops—Okinokitaiwa, Okinominamiiwa, and Tobise. In terms of distance, this unpopulated archipelago is roughly 170 km north of Ishigaki Island, approximately 410 km west of Okinawa Prefecture, approximately 330 km from mainland China, and around 170 km northeast of Taiwan.
Image 1: The Senkaku/Diaoyu islands
Source: Wikimedia Commons, Jackopoid
The Senkaku or Diaoyu islands are of great importance not only to Japan, China and Taiwan, but also to extra-regional actors heavily invested in the region. The Senkaku/Diaoyu islands impact the triangle of relations between Japan, China and Taiwan, sea lanes of communication (SLOC), and the application of conventional maritime law in the region.
Early Historical Records and Claims
In the 12th century, three scattered principalities on Okinawa Island—Hokuzan (northern mountain), Chūzan (central mountain), and Nanzan (southern mountain)—were unified and emerged as the kingdom of Ryukyu. In 1372, King Satto/Chadu was honoured with the title of “King of Chūzan” and accepted tributary status under the Ming Dynasty (1368 to 1644) when Emperor Hongwu of the Ming Dynasty dispatched an envoy to Ryukyu in his 5th year of reign.
As a tributary state, Ryukyu started formal trade relations with the Ming Dynasty, based on sulfur and textiles, until the end of the Qing Dynasty (1644–1912). Chinese envoys were sent to confer with the Ryukyu Kings with titles around 24 times, and according to Chinese historical records, the Diaoyu islands were located on their route to the Ryukyu Kingdom, fortifying the Chinese claim. However, by 1609, the Satsuma domain (trained samurai) of the Shimadzu clan seized the Ryukyu Kingdom, though it remained secret, and trade continued with the Chinese.
In the Meiji Era (1872-1879), Japan initiated coordinated political and security measures, one of which included the annexation of the Ryukyu Kingdom and renaming it the Okinawa Prefecture, which subsequently led to tensions between Japan and China. In April 1880, an attempt was made to settle the dispute when Japan proposed a draft treaty where both Japan and China agreed to divide Ryukyu into two, with Miyako-jima (宫古岛) and the Yaeyama islands (八重山群岛) to be given to China and the northern part to be ceded to Japan. However, Japan never implemented the treaty and continued to administer control of the islands till the end of WWII.
On 17th April 1895, the Treaty of Shimonoseki was signed between China and Japan after China’s defeat in the First Sino-Japanese War (1894-1895). Article II (b) laid down that China cedes to Japan, among other territories, ‘the island of Formosa (referring to present-day Taiwan), together with all islands appertaining or belonging to the said island of Formosa.’ Before this, the Japanese government conducted surveys through agencies of Okinawa Prefecture on the contested islands and found them uninhabited (terra nullius) with no trace of any state ruling the islands, negating China’s claims.
Months before the treaty, on 12th January 1895, the Japanese cabinet prepared a document to incorporate ‘the Senkaku islands (Uotsuri and Kuba islands)’ under the jurisdiction of the Okinawa Prefecture. On the 14th of January, the cabinet approved the document, with no objection to the decision permitting Okinawa Prefecture to have jurisdiction over the islands. (Image 2).
Image 2: The document contains the text of the cabinet approving jurisdiction over the Senkaku islands
Source: Cabinet Secretariat of Japan
After the incorporation of the islands for decades, Japan exercised undisputed administrative control of the islands till 1941, when China declared war against Japan, taking back its territory and countering Japan’s expansionist policies. On 1st December 1943, the leaders of the United States, Britain, and China jointly announced the Cairo Declaration, which stipulated that Japan return the territories captured during the First Sino-Japanese War. The terms of the Cairo Declaration continued in the Potsdam Proclamation, whose paragraph 8 states that ‘Japanese sovereignty shall be limited to the islands of Honshu, Hokkaido, Kyushu, Shikoku and such minor islands as we determine.’ This made the dispute more complicated by presenting both Japan and China with a vague definition and not clarifying the maritime boundary.
Image 3: Japanese PM Kakuei Tanaka and Chinese Premier Zhou Enlai toast together on September 28, 1972
Source: AP Photo
After WWII, the San Francisco Peace Treaty placed the Senkaku/Diaoyu islands under the United States' (US) administration. The administrative rights of these islands were restored to Japan in 1972, after protests from the People’s Republic of China (PRC) and Taiwan (ROC). Notably, from 12 October to 29 November 1968, the United Nations (UN) conducted a survey that reported potential oil reserves in the waters of the ECS, which triggered claims around these islands.
On 29 September 1972, the governments of Japan and China issued a joint communique to restart diplomatic engagement. In this joint communique, the government of Japan accepted that ‘Taiwan is an inalienable part of the territory of the People's Republic of China’ (Image 3). After the joint statement, both countries made efforts to negotiate on matters such as trade, shipping, aviation, and fisheries, temporarily shelving the island dispute. Against this backdrop, after Deng Xiaoping visited Japan on 12 August 1978, the Sino-Japanese Treaty of Peace and Friendship was signed. The objective of the treaty was to foster closer relations and development and, crucially, regional peace and stability. By 1986, bilateral trade between the two countries stood at USD 15.5 billion.
According to Chapter 1 (D) of Japan’s Diplomatic Bluebook of 2001, total trade between China and Japan reached 7.5 trillion yen in 1999 and then 9.2 trillion yen by 2000. Despite regular confrontation at sea, in 2024, total trade reached USD 292.6 billion, with China importing telecommunications equipment, computer parts, clothing, etc., reflecting trade interdependence between the two nations. The economic interdependence between China and Japan achieved record levels as they shelved the dispute over the islands. However, Japan purchased and nationalised the islands in 2012, reigniting the island dispute. In response, Beijing released a white paper titled "Diaoyu: The Inherent Territory of China," reasserting its claim to the contested islands. To counter it, Japan’s Foreign Ministry (MOFA) substantiated its claims, refuting China and clarifying any uncertainty about the island’s sovereign status.
Competing Claims and Legality
The Senkaku/Diaoyu dispute revolves around the competing sovereignty claims of Japan, China and Taiwan. Each disputant has different historical, legal and political arguments relating to ownership of these islands. Japan believes that there is ‘no issue of territorial sovereignty’ related to the Senkaku islands and maintains that they are an inherent part of its territory, incorporated in 1895. Tokyo maintains that the islands were terra nullius, or belonged to no state, before it took administrative control of them. One of Japan’s compelling arguments is its consistent authority over the islands, conforming to international law.
China argues that its ancestors discovered the islands, engaged in fishing activities, and named them the Diaoyu. Also, it claims that these islands have been a part of China since the Ming dynasty. China cites travel records of envoys, reports, maps, and navigation markers as evidence that the islands were the inherent territory of China before Japan’s incorporation. China claims one of the earliest records to include the name of Diaoyu is the ‘Voyage with a Tail Wind' (顺风相送), written in the 14th century during the Ming dynasty. China claims that one of the outcomes of the first Sino-Japanese War (1894-1895) was that Japan seized the islands, and they should be returned. China’s official stance rejects Japan’s authority and its claims that the islands were uninhabited. It asserts its claims by fishing and patrolling the region using domestic maritime vessels, operated by the Chinese Coast Guard (CCG) and the Chinese Maritime Militia (CMM).
Taiwan also rejects Japan’s argument that the islands were uninhabited and draws similar historical evidence to that provided by China. Taipei claims that the islands are an inherent part of its territory. According to Taiwan’s perspective, the islands were discovered by the Ming dynasty. And there is no recorded evidence that the islands were uninhabited. The ROC asserts that Chinese envoys used the islands as their navigation markers, and Taiwanese fishing communities have long survived around these islands.
Resource Competition
History and sovereignty are not the only factors that define the issue of the Senkaku/Diaoyu islands. The region surrounding the disputed islands also has hydrocarbons (essential for energy security) and fisheries, adding to the economic value of these islands in this competitive arrangement between Japan, China and Taiwan. The focus on natural resources increased after a mineral survey was conducted by the UN in 1968. The survey concluded that the waters of the ECS indicate potential oil and gas reserves. In the 1970s, Taiwan started petroleum exploration in the region, which Tokyo protested, as the area overlapped with Japan’s territory.
Japan considers the median line as the maritime boundary between Japan and China, but China rejects it, as there is no agreed-upon maritime boundary. On the other hand, China asserts a 200-nautical-mile EEZ and continental shelf. However, without a clear maritime boundary between Japan, China and Taiwan, the exploration of natural resources has been limited. In 2008, Japan made efforts to undertake peaceful exploration on the seabed of the ECS, but these efforts ultimately failed after Japan arrested Chinese fishermen around the Senkaku islands. Tensions escalated further in 2012, when Japan nationalised three of the islands, and China commenced regular patrolling.
Fisheries are another important dimension of this dispute. The waters around the islands have fertile fisheries, and the fishing communities of Japan, China and Taiwan depend on these islands. Access to islands may not affect the governments of these claimant countries, but it impacts the livelihood of the fishing communities residing near them. In this context, on 10 April 2013, the Taiwan-Japan Fisheries Agreement was signed between Japan and Taiwan to regulate fisheries-related matters and enable fishing communities on both sides to pursue their fishing activities. To monitor the agreement, the Taiwan-Japan Fishery Committee (TJFC) was created, acting as a coordination platform for both countries. However, both sides continue to maintain their claims of sovereignty.
Military Strategies
China employs the CCG, CMM, and fishing vessels as part of its grey-zone strategy in the ECS and regularly operates near the Senkaku islands. Grey-zone tactics are coercive actions that fall below the threshold of open or direct war yet alter the status quo and challenge conventional maritime law. China employs an Anti-Access/Anti-Denial (A2AD) posture in the ECS, which combines air defense zones, regular coast guard patrols, and active military presence to challenge Japan’s administration of the Senkaku islands. For instance, on 23 November 2013, China announced an Air Defense Identification Zone (ADIZ) which covers a wide area of the ECS, including the airspace of the Senkaku/Diaoyu islands. By employing ADIZ, China asserts control over the disputed airspace without using force. Moreover, this creates legal ambiguity regarding the ownership of the islands. For instance, on 29 November 2013, China deployed aircraft in response to two US planes and ten Japanese aircraft, including F-15 fighters, entering the airspace of the ECS.
Similarly, Japan’s white paper states that CCG operates regularly in the contiguous zone and repeatedly intrudes into Japan’s territorial waters around the Senkakus. To challenge Japan’s control, CCG vessels were recorded near the islands for 353 days out of 365 in the year 2024. It reflects China's denial strategy that reinforces sovereignty claims, complicating Japanese and US access around the island without open warfare. Japan’s military strategy centres on the principle of effective control to preserve its administrative authority through defensive patrol and alliance coordination. Japan uses the Japan Coast Guard (JCG) as the first responder for policing to avoid military confrontation and deter China. Japan’s Self-Defense Forces (JSDF) conduct regular air scrambles from the Okinawa bases to monitor Chinese vessels and aircraft.
Taiwan’s strategy emphasizes the deployment of Coast Guard Administration (CGA) vessels to conduct patrols and sustain a symbolic presence around the islands while avoiding direct confrontation with either Japan or China. Taiwan established an ADIZ in 1952 with US assistance, encompassing more than 150,000 square nautical miles, well before the creation of China’s ADIZ. In addition, Taiwan has made significant arrangements with Japan on fisheries. For example, Taipei has signed the Taiwan-Japan Fisheries Agreement with Tokyo to allow fishing access while shelving the sovereignty dispute.
The Current Security Environment
The security environment in the ECS is highly tense, defined by regular Coast Guard confrontations, military escalations, and fisheries accidents, posing a serious threat to regional security. In the past few years, the confrontation over the Senkaku/Diaoyu islands has intensified, with increased Chinese naval presence and strong Japanese defensive measures. For instance, on 7 September 2010, an incident was reported of a Chinese trawler that collided with a JCG vessel near the islands. This incident led to a temporary deterioration in the bilateral relations of Japan and China. Similarly, in 2025, the CCG vessels entered Japan’s territorial waters around the islands 27 times and sailed in Japan’s contiguous zone around the Senkaku islands, a record 357 times last year. This sudden spike in the number of vessels entering Japan’s territorial zone not only threatened Tokyo’s sovereignty but also redefined what is usually called the ‘new normal’ for the ECS.
Notably, in February 2021, the Coast Guard Law of China (中华人民共和国海警法) came into effect. It sets out the ‘authorities and powers’ of the coast guard and contains provisions such as the use of force against foreign vessels in China’s claimed maritime territory. With domestic legal backing, in 2021 alone, the Chinese Coast Guard (CCG) entered the contiguous zone 332 days out of 365 days and made 40 territorial intrusions. Subsequently, incidents of illegal foreign fishing boats and research vessels have continued to rise in the Japanese EEZ around Yamatotai. Japan’s actions (issuing warnings and using water cannons) to deter China have been focused on law enforcement in the region without escalating the dispute, according to Japan’s Coast Guard report of 2022.
Recently elected Japanese PM Sanae Takaichi, a known critic of China, made a statement in the Diet that Tokyo would use ‘military action’ if Beijing launched an attack on Taiwan, reflecting a rhetorical shift and inviting criticism from China. After a diplomatic crisis between the two countries, in December 2025, two CCG vessels entered Japanese territory but were expelled by the JCG. Although a spokesperson of CCG, Liu Dejun, stated that China warned off a Japanese fishing vessel that "illegally entered the territorial waters of China's Diaoyu Dao" and called on Japan to cease patrol activities in what it described as Chinese territory. Moreover, under PM Sanae’s rule, China is targeting economic ties with Japan. For example, China has restricted imports of Japanese seafood and suspended major Chinese airlines from operating flights to Japan. In November 2025, 540,000 air tickets to Japan were cancelled. Furthermore, China banned the supply of rare earth elements to Japan, which contributes 60% to its rare earth imports.
The recent dispute around the Senkaku islands is characterised by high-frequency maritime confrontations. This dynamic of interaction between regional navies has made the current security environment in the ECS highly volatile.
Regional Implications
The Senkaku/Diaoyu island dispute is one of the most active flashpoints in broader East Asia, codifying the debate around regional security, alliances, and international maritime order. China’s aggressive posture and efforts to alter the maritime order of the ECS is closely linked to Japan’s alliance signalling. Moreover, the US naval presence through joint maritime exercises and Freedom of Navigation Operations (FONOPs) poses a containment threat to China. In 2021 alone, the US Navy and the Japan Maritime Self-Defense Force (JMSDF) conducted 23 joint exercises around the Senkaku islands. More recently, in January 2024, the US, Japan, and South Korea conducted a trilateral drill in the ECS, aimed at strengthening alliance deterrence amid tensions around the Senkaku islands.
Moreover, the economic interdependence of states in the region could amplify the effects of the dispute. Sea lanes carrying most of the commercial shipping in Asia and Europe pass through these islands. SLOCs carry roughly USD 7.4 trillion in annual trade, underscoring the strategic importance of ECS shipping routes. According to the US Energy Information Administration (EIA), approximately 35% of global petroleum shipments transit through the ECS.
The Senkaku/Diaoyu Island dispute in the ECS remains highly volatile and is characterized by China’s grey-zone tactics, characterised by maneuvers of the CCG and CMM, leveraging of the ADIZ and Coast Guard Law. At the same time, Japan’s response is channelled through the principle of effective control, regular patrols, and alliance coordination. With a significant enhancement of Japan’s defense capabilities and the deployment of JSDF warships and reconnaissance assets around Okinawa, regional tensions around the ECS remain a flashpoint for China-Japan relations.
Author
Afridi Ahmed
Afridi Ahmed is a Research and Administrative Intern at Organisation for Research on China and Asia (ORCA). He is a postgraduate in Conflict Analysis and Peacebuilding from Jamia Millia Islamia, New Delhi. He has previously interned with the Council for Strategic and Defense Research (CSDR), a New Delhi-based think tank. His research interests include strategic studies, Indo-Pacific security, China's strategic behaviour, and maritime geopolitics, with a particular focus on South and Southeast Asia.