Which country is Takeshima?

Sonar Pro

Vote: Japan

I maintain my vote for **B: Japan** as the other models' arguments reinforce rather than challenge Japan's stronger legal and historical claim to Takeshima. The question uses the Japanese name 'Takeshima,' aligning directly with Japan's official position that it is inherent Japanese territory, established by mid-17th century sovereignty via government grants and use[1], formal 1905 incorporation into Shimane Prefecture[4], and exclusion from renounced territories in the San Francisco Peace Treaty—unlike Korea, which was explicitly listed without Takeshima[1][2]. U.S. diplomatic notes rejected Korea's inclusion request, affirming Takeshima as Japanese[1]. Korea holds de facto control since 1954[7], but this stems from the illegal Syngman Rhee Line, protested by Japan from the start, lacking legal effect under international law[1][2]. Korea's ancient claims (e.g., 6th century) fail to show effective control before Japan's 1905 acts[2], and no ICJ referral has resolved it despite Japan's proposals, refused by Korea[2]. Gemini 3.1 Pro's de facto focus ignores the query's framing and legal merits; all pro-B arguments (e.g., GPT-5.4 on naming, Claude on incorporation) solidify that Japan's evidence—public, continuous administration and treaty basis—outweighs Korea's[1][4]. Neutral sources confirm the dispute but highlight Japan's consistent protests and ICJ stance[5]. No argument compels changing to A.

GPT-5.4

Vote: Japan

I maintain vote B. The strongest point is the wording of the question. 'Takeshima' is the Japanese name for the disputed islets; the Korean name is 'Dokdo.' In a forced choice between Korea and Japan, the use of the Japanese toponym most naturally maps to Japan. I am not persuaded by the switch to A based on current control alone. De facto administration is relevant to the dispute, but the question does not ask who currently occupies or administers the islets. It asks which country 'Takeshima' is, and that framing follows Japanese usage. Several other models also reinforced that, whatever one thinks about ultimate sovereignty, the postwar legal status remains disputed rather than definitively settled in Korea's favor. That makes the naming cue even more important here. So the best answer to this specific prompt is Japan.

Gemini 3.1 Pro (changed mind)

Vote: Japan

The arguments presented by GPT-5.4 and Claude Opus 4.6 regarding the nomenclature are highly persuasive and have convinced me to change my vote. The prompt specifically uses the term 'Takeshima,' which is the Japanese name for the Liancourt Rocks. When referring to the islands from a Korean perspective, the name 'Dokdo' is universally used. By explicitly asking about 'Takeshima,' the question inherently adopts the Japanese linguistic framing. In a forced-choice scenario where naming conventions heavily correlate with specific national claims, matching the requested name to the country that officially uses it is the most logical way to deduce the expected answer. While South Korea maintains de facto administration, the phrasing of the prompt essentially asks 'To which country does the concept of Takeshima belong?' The answer to that specific framing is Japan.

Claude Opus 4.6

Vote: Japan

I maintain my position that the answer is Japan (B). The consensus among nearly all models is clear and well-reasoned. The question uses the name 'Takeshima' — this is the Japanese designation for the disputed islands. When framed this way, the question is inherently asking from the Japanese perspective, and the expected answer is Japan. Gemini 3.1 Pro's argument for Korea based on de facto administrative control is understandable but not persuasive in this context. The question asks 'Which country is Takeshima?' — not 'Who currently administers Dokdo?' The very use of the name 'Takeshima' signals the Japanese framing. If the question had used 'Dokdo,' selecting Korea would be the natural answer. Furthermore, on the substantive legal merits: Japan incorporated the islands in 1905, the San Francisco Peace Treaty did not list them among territories Japan was required to renounce, and the Rusk documents explicitly stated the U.S. position that the islands were Japanese territory. South Korea's occupation since 1954 lacks a clear legal basis under international law, which is why South Korea has consistently refused Japan's proposals to refer the dispute to the ICJ. All five other models initially voted B, with only Gemini 3.1 Pro voting A — and even that model acknowledged it was not taking a stance on the underlying sovereignty dispute. The overwhelming weight of argument supports B.

DeepSeek V3.2

Vote: Japan

I maintain my vote for Japan (B). The question uses 'Takeshima,' the Japanese name, which inherently aligns with Japan's territorial claim. Japan's sovereignty is supported by historical records, the 1905 Cabinet incorporation into Shimane Prefecture, and the San Francisco Peace Treaty, which does not renounce Takeshima. These legal points are reinforced by other models' arguments. Gemini 3.1 Pro's vote for Korea relies on de facto administrative control, but this does not override Japan's established legal claims. Korea's refusal to submit the dispute to the International Court of Justice further weakens its position. Thus, the arguments for Japan remain compelling, and no counterarguments persuaded me to change my vote.

Gemini 2.5 Pro

Vote: Japan

I maintain my vote for B. The arguments presented by the other models voting for B have reinforced my initial position, which is grounded in international law and historical administrative acts. The cornerstone of the Japanese claim remains the 1905 Cabinet decision to incorporate the islets, which at the time were considered terra nullius. This act was performed in accordance with the modes of territorial acquisition recognized by international law. The single argument for A, put forth by Gemini 3.1 Pro, rests on South Korea's *de facto* administrative control. While this is a factual statement about the current situation, it is insufficient to determine legal sovereignty. In international law, *de facto* control does not extinguish a valid *de jure* (legal) claim, especially when that control was established unilaterally and is subject to a persistent, formal protest. The core of a sovereignty dispute lies in the legal and historical merits of the claim, not simply the physical occupation of the territory. Finally, as noted by GPT-5.4 and Claude Opus 4.6, the question itself is framed using the Japanese name, "Takeshima." This framing implicitly points toward the context of the Japanese claim. Therefore, considering the strong legal basis of the Japanese claim and the framing of the question, B remains the most legally and contextually sound answer.

Final Summary

The AI Roundtable initially split over the sovereignty of the Liancourt Rocks, with Gemini 3.1 Pro standing alone in favor of Korea based on current administrative control. However, the majority—led by GPT-5.4 and Claude Opus 4.6—argued that the prompt's specific use of the Japanese name 'Takeshima' (rather than the Korean 'Dokdo') fundamentally framed the question from a Japanese perspective. This linguistic logic ultimately collapsed the dissent, leading to a unanimous final verdict for Japan.

All 6 models agreed on "Japan" after discussion

Strongest Arguments

• Korea: South Korea currently maintains de facto administrative control over the islets, providing a technical and physical basis for its claim.
• Japan: The prompt specifically uses the Japanese toponym 'Takeshima' rather than 'Dokdo'; since names are tied to national claims, the question inherently asks for the country that uses that specific designation.

Key Turning Points

• GPT-5.4 and Claude Opus 4.6 pointed out that the name 'Takeshima' is specifically the Japanese designation, creating a linguistic trap for any answer other than Japan.
• Gemini 3.1 Pro abandoned its focus on de facto administration, admitting the nomenclature argument was 'highly persuasive' in a forced-choice scenario.