尖閣諸島は日本の領土か？

Grok 4.20

Vote: Yes

The Senkaku Islands (Diaoyu/Diaoyutai to China/Taiwan) have been under continuous Japanese administration since 1895, following surveys showing them as terra nullius. They are officially part of Okinawa Prefecture. No Chinese government exercised control or even protested until the 1970s, after a UN report suggested possible undersea oil resources. Historical records, including Chinese maps from the Ming and Qing eras, treat the islands as outside their territory. Under international law (including the Treaty of Shimonoseki and post-WWII agreements), Japan's sovereignty holds. The U.S. recognizes Japanese administration and has stated the islands fall under the U.S.-Japan Security Treaty. Effective control and legal precedent confirm they are Japanese territory despite the political dispute.

DeepSeek V3.2

Vote: Yes

The Senkaku Islands have been under Japan's effective control and administration since 1895, when they were incorporated into Japanese territory as terra nullius. Japan's sovereignty was reaffirmed post-World War II by the San Francisco Peace Treaty and the return of administrative rights from the U.S. in 1972. Japan has continuously maintained control, including patrols and infrastructure, without challenge until the 1970s when resource interests arose. Historical documents, such as those from the Ming and Qing dynasties, do not show Chinese administration, further supporting Japan's claim under international law.

GPT-5.4

Vote: Yes

国際法上・実効支配の観点からは、日本の領土とみる根拠が強いです。 日本は1895年に無主地先占の手続きを経て編入し、その後も行政権を行使してきました。戦後も沖縄の施政権返還に伴い日本が継続して管理しています。 中国・台湾が本格的に領有権を主張し始めたのは比較的 поздい時期で、特に1970年代以降です。この点は先行する日本の支配と対比されます。 現在も日本が継続的かつ平穏に実効支配しており、国際紛争論としては別論があっても、設問に二択で答えるならAが妥当です。

Gemini 3.1 Pro

Vote: Yes

尖閣諸島は、歴史的にも国際法上も日本固有の領土です。日本政府は1895年、他国の支配が及んでいない無主の地（無人島）であることを長年にわたり慎重に確認した上で、国際法に則り正当に日本の領土に編入しました。 また、第二次世界大戦後のサンフランシスコ平和条約においても、尖閣諸島は日本の領土として確定した上で一時的に米国の施政下に置かれました。その後、1972年の沖縄返還協定に伴い、施政権が日本に返還されています。 現在も日本が有効に支配・管理を行っており、歴史的経緯と国際法の両面から見て、日本の領土であることは明らかです。

DeepSeek V3.1

Vote: Yes

The Senkaku Islands are unequivocally Japanese territory based on historical and legal grounds. Japan has administered the islands since 1895, when they were formally incorporated into Okinawa Prefecture after a survey confirmed they were uninhabited and without prior ownership. International law supports Japan's sovereignty, as the islands were not included in territories Japan renounced after World War II under the San Francisco Peace Treaty. China's claims, which emerged only in the 1970s following potential resource discoveries, lack substantiated historical evidence and contradict earlier maps and documents that recognized Japanese control. Japan maintains continuous and peaceful administration, including lighthouse construction and coast guard patrols, reinforcing its effective control. While disputes exist, they do not undermine the legitimacy of Japan's claim, which is upheld by consistent state practice and international recognition.

Final Summary

The AI Roundtable reached a swift and unanimous consensus, with all five models identifying the Senkaku Islands as Japanese territory. Led by a shared emphasis on the 1895 incorporation and continuous effective administration, models like Grok 4.20 and DeepSeek V3.1 argued that historical and legal precedents significantly outweigh late-blooming resource-driven claims.

All 5 models agreed on "Yes" after discussion

Strongest Arguments

• Yes: The islands were incorporated as terra nullius in 1895 following extensive surveys, and Japan has maintained continuous, peaceful, and effective administration since then, a status reinforced by the 1972 Okinawa Reversion Agreement and the lack of international protest until potential oil resources were identified in the 1970s.