Why are the Senkaku Islands disputed? Because Japan, China, and Taiwan each claim a group of uninhabited rocks in the East China Sea on competing readings of history and law, and because the surrounding waters hold fisheries, shipping lanes, and possible seabed resources. Japan administers the islands and says they were legally incorporated in 1895 as unclaimed land. China, which calls them the Diaoyu Islands, argues that they were Chinese territory long before and should have been returned after 1945. Taiwan makes a similar claim to China's.
This article separates the dispute into its layers: the geography, the competing historical narratives, the postwar legal arguments, the economic and strategic stakes, and the incidents that turned a quiet disagreement into a recurring confrontation. The central point is that the dispute is not only about the rocks. It is also about how two treaties, a wartime defeat, and later maritime law each get read, and about what the islands would mean for control of surrounding waters.
The Islands and Their Setting
Geography of a Small Archipelago
The Senkaku Islands consist of five small uninhabited islets and three rocks, with a combined land area of only a few square kilometers. They lie in the East China Sea roughly 170 kilometers northeast of Taiwan, about 330 kilometers from the Chinese mainland, and about 410 kilometers southwest of Okinawa. The largest island, Uotsuri, is the one most often pictured in news coverage.
Their small size is part of the puzzle. Nobody lives there permanently, and the terrain is steep and rugged. In the early twentieth century a Japanese businessman, Koga Tatsushiro, ran a bonito-processing operation on some of the islands, which collapsed by the 1940s. Since then the islands have had no lasting settlement, so claims rest on law and history rather than on communities that live there.
Three Names, Three Claimants
Japan uses the name Senkaku, derived from an English translation of a Western name, and China uses Diaoyu, meaning fishing platform. Taiwan uses the Chinese name as well. The naming difference signals the political split: using either name in diplomacy is often read as a position, which is why international media sometimes give both.
The three claimants are not equally placed. Japan has held administrative control since the early 1970s, when the United States returned Okinawa, and it maintains that no territorial dispute exists. China and Taiwan contest that position. Because the People's Republic and the Republic of China each claim to be the legitimate government of China, their claims overlap in content but are advanced separately.
Competing Historical Narratives
Japan's Case: 1895 Incorporation
Japan's argument is that surveys beginning in 1885 found the islands uninhabited and showing no trace of control by the Qing dynasty. On January 14, 1895, the Japanese cabinet approved erecting boundary markers, treating the islands as terra nullius, land belonging to no state. Tokyo stresses that this occurred before the Treaty of Shimonoseki was signed in April 1895, and therefore was not part of the territory China ceded after the First Sino-Japanese War.
Japan adds that after World War II, the islands were not included in the territories it renounced in the 1951 San Francisco Peace Treaty. They were instead placed under United States administration as part of the Nansei Shoto, and returned to Japan with Okinawa under the 1971 reversion agreement, which took effect in 1972. For Tokyo, this shows continuous and legitimate title.
China's Case: Earlier Discovery and Cession
China points to Ming and Qing records that mention the islands as navigation markers, and argues that they were used by Chinese fishermen and were part of coastal defense planning. Chinese statements say the islands belonged to Taiwan and were taken by Japan as part of the cession of Taiwan in the Treaty of Shimonoseki. On this reading, the postwar Cairo and Potsdam declarations required their return.
Japan answers that historical mentions as navigation aids do not establish sovereignty, and that China raised no objection for decades, including when maps and statements in the 1950s and 1960s appeared to treat the islands as Japanese. China replies that its silence was not acquiescence and that the San Francisco treaty, which it did not sign, could not decide the question. Scholars outside the two governments are divided, and the evidence is contested on both sides.
What makes the narratives hard to reconcile is that each rests on a different starting date. If the legal story begins in 1895, Japan's case is stronger. If it begins with Ming-era knowledge, or with the postwar settlement, China's arguments gain weight.
Why the Dispute Surfaced in 1968-1971
The Seabed Survey
For about two decades after the war, the islands drew little public attention. The turning point came after a United Nations survey in 1968, sponsored by an Asian regional economic body, suggested that the continental shelf beneath the East China Sea might hold significant oil and gas reserves. Shortly afterward, Taiwan and then the People's Republic began to assert claims openly.
The timing is often cited as evidence that resources, not history, triggered the dispute. Chinese and Taiwanese officials counter that the claims are rooted in earlier history and that the survey merely made the issue urgent. Actual reserves remain uncertain, and exploration has been limited by the dispute itself.
Okinawa Reversion and the Normalization Talks
The second trigger was the planned return of Okinawa from United States administration to Japan, agreed in 1971. Because the islands were included in the area being returned, Beijing and Taipei protested. Washington stated that it took no position on ultimate sovereignty, while maintaining that the islands fell under the 1960 security treaty with Japan as territory under Japanese administration.
When China and Japan normalized relations in 1972, the issue was reportedly set aside. Accounts of the talks say that leaders chose not to resolve it, and in 1978 Deng Xiaoping said that a later generation might have the wisdom to settle it. The two governments have since disagreed about whether an understanding to shelve the matter ever existed, with Japan denying that any such agreement was made.
This ambiguity helps explain why the dispute remained dormant for decades yet could reignite whenever the political climate shifted.
The Stakes: Law, Resources, and Strategy
Maritime Zones and the Law of the Sea
Under the 1982 United Nations Convention on the Law of the Sea, a coastal state may claim a 12-nautical-mile territorial sea and an Exclusive Economic Zone extending up to 200 nautical miles, within which it controls fishing and resource extraction. Islands that can sustain human habitation or economic life generate such zones, while mere rocks generate only a territorial sea. Whether the Senkaku features count as islands or rocks is itself disputed.
Because the East China Sea is narrower than 400 nautical miles, the zones claimed by Japan and China overlap. Control of the islands would therefore influence the drawing of a maritime boundary across a large area. Japan favors a median line between the two coasts, while China argues for a boundary reflecting the natural extension of its continental shelf.
Strategic and Alliance Dimensions
The islands lie near sea lanes carrying much of the region's trade and close to routes linking the Chinese coast with the Western Pacific. Analysts note that control of the area could ease or complicate naval movement. For Japan, giving ground would also set a precedent for other territorial disputes, including those with Russia and South Korea.
The United States has repeatedly said that Article 5 of its security treaty with Japan covers the Senkaku Islands, which makes the dispute an alliance matter. Presidents from Barack Obama onward have affirmed the position while repeating that Washington does not take a stance on sovereignty. This combination of neutrality on title and commitment on defense is a subtle formula that both Tokyo and Beijing watch closely.
So the stakes include fish, possible hydrocarbons, maritime boundaries, naval access, and alliance credibility. No single factor explains the dispute, but together they make the islands more valuable than their size suggests.
From Dormant Dispute to Standoff
The 2010 and 2012 Crises
In September 2010, a Chinese fishing trawler collided with two Japanese Coast Guard vessels near the islands. Japan detained the captain, and the episode led to a diplomatic crisis in which China reportedly restricted exports of rare earth materials to Japan, though Beijing denied an official embargo. The captain was released after about two weeks.
In September 2012, the Japanese government purchased three of the islands from a private Japanese owner. Tokyo said the purchase was meant to prevent the nationalist governor of Tokyo, Ishihara Shintaro, from buying them and provoking a worse confrontation. Beijing saw it as a change in the status quo, and large anti-Japanese protests followed in Chinese cities.
Coast Guard Presence and Gray-Zone Pressure
Since 2012, Chinese coast guard vessels have entered the waters around the islands regularly, and Japan has reported frequent incursions into the contiguous zone and periodic entry into the territorial sea. In November 2013, China declared an air defense identification zone over much of the East China Sea that included the islands, which Japan and the United States rejected.
Analysts describe this pattern as gray-zone pressure: activity below the threshold of armed conflict that tests the other side's resolve and builds a record of presence. Japan has responded by strengthening its coast guard and by reinforcing military posture in its southwestern islands. Because most incidents involve civilian vessels, escalation to open conflict has so far been avoided.
Readers should consult current reporting for the latest incidents, since coast guard activity and diplomatic positions continue to change.
Can the Dispute Be Resolved?
Legal and Diplomatic Options
Courts could in principle decide the question, but Japan holds that no dispute exists and so sees nothing to submit, while China has not accepted international adjudication of territorial claims. The 2016 arbitration ruling in the South China Sea case, which China rejected, reinforced Beijing's wariness of legal processes it does not control.
Diplomacy has produced partial tools instead. Japan and China have set up maritime communication mechanisms and hotlines to reduce the risk of accidents, and a 2008 understanding on joint development of East China Sea gas fields was announced though it never made much practical progress. Such arrangements manage risk but leave the question of sovereignty untouched.
Why Compromise Is Hard
A settlement would require each government to concede something that its domestic politics treats as non-negotiable. In Japan, ceding any claim would be politically costly, and in China, accepting Japanese control would be read as accepting a legacy of defeat and humiliation. Nationalist sentiment on both sides raises the price of flexibility.
The most likely path is continued management rather than resolution. The disagreement persists because the islands combine legal ambiguity, resource hopes, strategic position, and national memory, and each of those factors strengthens the others. Understanding the dispute therefore means holding all of these layers together rather than searching for a single cause.