Best AI models for Japanese
Product Japanese fails easily on keigo (丁寧語) and natural phrasing. Claude, Gemini, and GPT usually lead; Kimi adds long context useful for JP docs. All on one Geek Hub API.
Models in this collection
| Model | Type | Context | Price |
|---|---|---|---|
 Claude Sonnet 5Anthropic | Chat | 1M tokens | $3.2702/M in · $16.3509/M out |
 Gemini 2.5 ProGoogle | Chat | 2M tokens | $1.3626/M in · $10.9006/M out |
 GPT-5.5OpenAI | Chat | 272k tokens | $5.4503/M in · $32.7018/M out |
| Claude Opus 5Anthropic | Chat | 1M tokens | $5.4503/M in · $27.2515/M out |
| Gemini 2.5 FlashGoogle | Chat | 1M tokens | $0.327/M in · $2.7251/M out |
| GPT-5.4 miniOpenAI | Chat | 272k tokens | $0.8175/M in · $4.9053/M out |
 DeepSeek V4 ProDeepSeek | Chat | 1M tokens | $0.4742/M in · $0.9484/M out |
 Kimi K3Moonshot (Kimi) | Chat | 1M tokens | $3.2702/M in · $16.3509/M out |
Why these models
Claude/Gemini/GPT for conversational quality; Opus when tone is critical; Flash/mini for volume; Kimi/DeepSeek for cost/context.
Use them with Geek Hub
One OpenAI-compatible base URL and API key. Swap any model id from this list without rewriting your client.
Get an API keyFAQ
- How do I request keigo?
- System prompt: 丁寧語 / ですます level and whether you want 尊敬語. Add few-shot examples.
- Kanji/okurigana?
- Modern models handle written JP well. Keep brand terms in a glossary.
- EN→JP translation?
- Yes; native review recommended for public copy.