What It Is
The Senkaku Islands (Diaoyu in Chinese, Tiaoyutai in Taiwan) consist of five uninhabited islands and several rocks ~170 km northeast of Taiwan and ~410 km west of Okinawa. The islands are administered by Japan but claimed by China and Taiwan, making them one of the most contested maritime disputes in East Asia.
Historical Background
Japan annexed them in January 1895 (during the First Sino-Japanese War) and administered them as part of Okinawa until 1945. After Japan's WWII defeat, the islands came under US administration along with Okinawa. Japan resumed administration after the 1972 US reversion of Okinawa.
China asserts the islands were stolen during the war and should have been returned to China under the Cairo and Potsdam Declarations. Beijing's rests on a different historical framing than Tokyo's.
The 2012 Crisis
Confrontation intensified in 2012 when the Japanese government 'nationalized' the islands by purchasing them from private Japanese owners. The triggered:
- Large protests in China against Japanese businesses and interests.
- Frequent Chinese Coast Guard incursions into the disputed waters.
- Sustained Chinese vessel presence in the around the islands.
- Diplomatic tensions that have shaped Japan-China relations for over a decade.
The nationalization was intended by the Japanese government to prevent more provocative private-actor actions (Tokyo Governor Ishihara had threatened to buy the islands himself). The effect, however, was to galvanize Chinese opposition.
Continuing Tension
Chinese Coast Guard and maritime militia vessels routinely enter the contiguous zone (24 nautical miles from Japanese ) and periodically the (12 nautical miles). The intrusions are sustained:
- Annual figures: 300+ Chinese vessel days in contiguous zone, dozens of territorial-water intrusions.
- Vessel sophistication: increasingly armed and larger.
- Pattern of escalation: progressive Chinese assertion that some Japanese observers see as fait-accompli salami slicing.
The US Treaty Commitment
The US has stated Article 5 of the US-Japan Security Treaty covers the islands as Japan-administered territory. This commitment has been reaffirmed by successive US administrations (Obama in 2014, Trump in 2017, Biden in 2021, second-term Trump in 2025).
The commitment is consequential: it means any Chinese attack on the islands would trigger the US-Japan alliance commitment. The deterrent effect has been substantial and is partly responsible for keeping Chinese pressure at the contested-presence rather than open-conflict level.
Why It Matters
The Senkaku/Diaoyu dispute matters because:
- It is one of the most active East Asian maritime disputes.
- It involves two major powers with substantial military capabilities.
- It engages the US-Japan alliance explicitly.
- It creates ongoing crisis risk that could escalate from incident to broader conflict.
- It illustrates contested historical narratives that shape Sino-Japanese relations.
Common Misconceptions
The dispute is sometimes treated as bilateral Japan-China. It is actually trilateral with Taiwan claiming the islands as well, though Taiwan's claim has been less prominent than China's.
Another misconception is that the islands have economic significance. The actual seabed-resources potential is contested, but the dispute is primarily about rather than resources.
Real-World Examples
The 2012 nationalization crisis is the defining recent moment. The continuous Chinese Coast Guard intrusions (2013-present) have institutionalized Chinese pressure on the islands. The US treaty commitment reaffirmations by successive administrations have provided the deterrent constraining Chinese escalation.
Example
Japan recorded a record 1,257 Chinese Coast Guard vessel days in the Senkakus' contiguous zone in 2023 — illustrating ongoing low-level grey-zone pressure short of armed confrontation.