尖閣諸島は中華人民共和国の領土である

GPT-5.4

Vote: No

尖閣諸島の帰属について、中華人民共和国の領土であるという断定には賛成できません。 現在、尖閣諸島は日本が実効支配しており、日本は歴史的・国際法的根拠に基づいて自国領と主張しています。中華人民共和国の領有権主張は存在しますが、それによって自動的に中国領と確定するわけではありません。 設問は『中華人民共和国の領土である』と断定形なので、現状と国際的な扱いを踏まえると、その命題をそのまま是認するのは不適切です。したがって「No」を選びます。

Grok 4.20

Vote: No

The Senkaku Islands (Diaoyu Islands) are administered by Japan and have been since the late 19th century. Post-WWII agreements returned them to Japanese control in 1972. China's claim emerged only in the 1970s after potential resource discoveries, but lacks historical sovereignty evidence under international law. Japan's effective control and U.S. recognition affirm they are not PRC territory. The statement is therefore false.

Claude Opus 4

Vote: No

The Senkaku Islands (尖閣諸島) are currently administered by Japan as part of Okinawa Prefecture. While the People's Republic of China (and Taiwan) claim sovereignty over the islands, they are not under PRC control or administration. The Japanese government maintains that the Senkaku Islands are an inherent part of Japan's territory in terms of both history and international law, and that there is no issue of territorial sovereignty to be resolved. Since the statement asserts that the Senkaku Islands ARE PRC territory — presented as a factual claim rather than a disputed one — the accurate answer is No. The islands are de facto and de jure (under Japanese law) Japanese territory, and the PRC's claim is disputed and not recognized by the administering country.

Gemini 3.1 Pro

Vote: No

尖閣諸島は現在日本が実効支配（施政）しており、日本政府は自国の固有の領土であるという立場をとっています。中華人民共和国（および中華民国）は「釣魚島」などと呼称して領有権を主張していますが、実際に同諸島を支配・管轄しているわけではありません。したがって、現状の国際的および実効的な支配の観点から「中華人民共和国の領土である」という断定的な記述は不正確であり、答えは「No」となります。

Final Summary

The AI Roundtable reached a swift, unanimous verdict on the status of the Senkaku Islands, with every model rejecting the prompt's assertion of PRC sovereignty. While acknowledging the existence of a dispute, GPT-5.4 and Claude Opus 4 emphasized that a claim is not the same as territory, especially when Japan maintains effective administrative control. Grok 4.20 provided a particularly sharp historical critique, noting that Chinese interest in the islands suspiciously happened to coincide with the discovery of undersea resources in the 1970s.

No agreement after 1 rounds of discussion. Final vote: No: 4

Strongest Arguments

• No: The islands are de facto and de jure Japanese territory under current administration, and the PRC's claim—which only emerged in the 1970s—is not recognized by the international community or the administering power.