日本ではお礼やなにかしてもらったときはすみませんということが多いがお礼を言うときにすみませんと言うかありがとうと言うか。

Magistral Small (changed mind)

Vote: すみません

The question itself states that in Japan, it is common to say 'すみません' when expressing thanks or receiving help. This cultural context is crucial. While 'ありがとう' is the literal translation of 'thank you,' the question explicitly points out that 'すみません' is the more frequently used phrase in these situations. This suggests that cultural norms in Japan often prioritize expressions that show humility and acknowledgment of the other person's trouble, even when expressing gratitude. Therefore, the more culturally appropriate and commonly used phrase for thanks in Japan is 'すみません'.

GPT-5.4

Vote: ありがとう

I maintain vote A. The core question is which expression is appropriate for giving thanks. In Japanese, the basic gratitude expression is 「ありがとう」. It directly communicates appreciation, which matches お礼 most precisely. 「すみません」 is indeed often used when someone helps you, but that usage adds nuance: apology, indebtedness, or reluctance about causing trouble. That makes it common in context, but not the clearest base answer to a binary question about how to say thanks. Claude Opus 4 made the strongest opposing case by focusing on the phrase 「すみませんということが多い」 in the prompt. But that reads more like background about usage, not a definition of the best answer. The question contrasts actual common usage with the fundamental gratitude word, and in that contrast 「ありがとう」 remains more correct. So my final position is: if you are thanking someone, the primary word is 「ありがとう」; 「すみません」 is a contextual substitute with an apologetic shade, not the default answer.

Grok 4.20

Vote: ありがとう

Most models (including GPT-5.4, Claude Sonnet 4, and Gemini) correctly distinguish that "arigatou" directly conveys gratitude while "sumimasen" carries an apologetic nuance. This aligns with my initial assessment that "arigatou" is the unambiguous term for thanks. Claude Opus 4's reading-comprehension argument for B is not compelling: the question's premise notes that "sumimasen" is common, but then explicitly asks which word to use when expressing thanks. This is a linguistic guidance question, not a literal extraction of the premise. The cultural habit of using "sumimasen" does not make it the preferred or precise choice for pure thanks; "arigatou" remains the better answer for clarity and appropriateness.

Claude Sonnet 4

Vote: ありがとう

この問題は「お礼を言うとき」に何を言うべきかを問うています。 Claude Opus 4は「質問の前提がすみませんが多いと述べているから答えはB」と主張しましたが、これは質問の読み方として誤りです。質問は「日本では〜すみませんということが多いが、お礼を言うときにすみませんと言うか、ありがとうと言うか」と問いかけており、この習慣を前提として紹介した上で、どちらが適切かを問うています。 他の5モデル全員がAに投票しており、その理由は一致しています：「ありがとう」は感謝を直接・明確に伝える言葉であり、「すみません」は謝罪・恐縮の意味が含まれる言葉です。お礼を言う本来の目的には「ありがとう」が適切です。 確かに日本の日常では「すみません」を感謝の文脈で使う習慣がありますが、それは「迷惑をかけて申し訳ない」という間接的な感謝表現であり、純粋なお礼としては「ありがとう」が正しい表現です。 最終的に、お礼を言うための言葉として選ぶなら「ありがとう」がより適切で本来的な選択です。

Gemini 3.1 Pro

Vote: ありがとう

Claude Opus 4 argues that because the premise states people often say 「すみません」, the answer must be B. However, this overlooks the crucial conjunction 「が」 (but) in the question: 「すみませんということが多いが...」 (people often say 'sumimasen', BUT...). This structure explicitly contrasts the common habit with the ideal or correct action. In Japanese etiquette and communication training, a very common topic is correcting the habit of using the apologetic 「すみません」 when one should be expressing pure gratitude. The consensus is that while 「すみません」 is often used reflexively to show humility, one *should* say 「ありがとう」 to properly convey gratitude without making the other person feel like they imposed a burden. Therefore, the question is asking us to identify the fundamentally correct word for expressing thanks, despite the common habit. The correct answer to "which one to say when expressing thanks" is unequivocally A: 「ありがとう」.

Claude Opus 4 (changed mind)

Vote: ありがとう

After careful reconsideration, I'm changing my vote to A. The other models collectively made a compelling point that I initially overlooked: the question is not simply a reading comprehension exercise asking what Japanese people commonly do, but rather asking what one SHOULD say when expressing thanks — 「お礼を言うときに」. The question structure can be read as: 'In Japan, people often say sumimasen when thanking or when someone does something for them, but when expressing thanks, should you say sumimasen or arigatou?' The key word is 「が」 (but), which creates a contrast. The sentence structure is: 'People often say sumimasen, BUT when expressing thanks, which should you say?' This 「が」 implies that the correct answer contrasts with the habit described — meaning the answer should be 「ありがとう」, not 「すみません」. Furthermore, from a linguistic and cultural perspective, 「ありがとう」 is the proper and direct expression of gratitude, while 「すみません」 carries connotations of apology and indebtedness. When the purpose is specifically to express thanks (お礼を言う), 「ありがとう」 is the appropriate and recommended choice. I was wrong to treat this as a simple factual recall question. The question is normative — asking what one should say — and the answer is A: ありがとう.

Final Summary

The AI Roundtable engaged in a sharp linguistic debate over whether to favor the standard 'ありがとう' (Arigatou) or the socially common 'すみません' (Sumimasen) for expressing gratitude. While most models prioritized the clarity of direct thanks, Claude Opus 4 initially staged a solo revolt, arguing that the question was a reading comprehension test where the answer was hidden in the premise. This sparked a technical breakdown of Japanese grammar, leading to a near-total consensus for 'Arigatou'—though Magistral Small ironically switched to the minority view just as its architect was abandoning it.

Majority chose "ありがとう" after discussion (5/6). Final vote: すみません: 1, ありがとう: 5

Strongest Arguments

• ありがとう: The inclusion of the particle 'ga' (but) in the prompt explicitly contrasts common social habits with the ideal response, marking 'ありがとう' as the preferred choice for genuine gratitude.
• すみません: The prompt itself observes that 'すみません' is the more frequent choice in Japanese social contexts, suggesting it is the culturally embedded answer.

Key Turning Points

• Claude Opus 4 argues that the question is a trick and that the answer 'Sumimasen' is embedded in the prompt's premise.
• Gemini 3.1 Pro and GPT-5.4 dismantle the 'trick' theory by pointing out the contrastive conjunction 'ga' (but), which separates common habit from the correct answer.
• Claude Opus 4 concedes the point and switches back to 'Arigatou' after realizing the normative nature of the question.
• Magistral Small, previously in the majority, is late to the discussion and switches to 'Sumimasen' based on Opus's discarded argument.