An AI chat service released in March 2026 by Sakana AI, an AI company based in Japan. It runs on “Namazu,” a large language model tuned for the Japanese language and Japanese business practices, and combines it with web search to answer using up-to-date information. Namazu is not a model trained from scratch; instead, Sakana AI applies its own post-training data to publicly available open models. The service emphasizes natural Japanese phrasing and a solid grasp of Japan-specific context and institutions. It runs in the browser and is free to use at the time of writing.
Key Features
- Namazu, a Japan-focused model: A model tuned for the Japanese language and Japanese business context. It is developed with an emphasis on Japanese that does not read like a translation, and on understanding domestic systems and conventions
- Web search integration: Instead of relying solely on the model’s internal knowledge, it can answer based on current information retrieved through web search, making it suitable for time-sensitive research
- Switchable response styles: Modes such as standard, polite, and Kansai dialect are available, so you can change the tone to suit the task or the audience
- File upload: You can load files from your machine to summarize or ask questions about their contents (the focus is local file upload rather than external storage integrations)
- Thinking mode: Beyond simple responses, a mode for slower, more deliberate reasoning is available for complex questions
- Sakana Namazu API: On August 3, 2026, an API version of the Sakana Chat model launched as “Sakana Namazu.” It uses an OpenAI-compatible API format, with web search and code execution available as built-in tools
Pricing
| Plan | Price | Highlights |
|---|---|---|
| Sakana Chat (web) | Free | Namazu model, web search, file upload, response style switching |
| Sakana Namazu (API) | See the official pricing page | OpenAI-compatible API, built-in web search and code execution |
Pricing is current as of August 2026. Check the official site and the Sakana AI blog for the latest information.
The chat service is offered free of charge at the time of writing. Paid plans or usage limits may be introduced later, so check official announcements before relying on it for ongoing business use.
Pros & Cons
✅ Pros
- Tuned with an emphasis on natural Japanese, so output is less likely to read like a translation and is often usable as-is
- Less likely to misread context in questions about Japanese systems, conventions, and proper nouns
- Combined with web search, it can handle topics that postdate the model’s training data
- Free to start, with no upfront investment beyond creating an account
- The same model is available through an API, so you can move from trial to integration without switching vendors
⚠️ Cons
- Compared with major overseas chat services, it offers fewer peripheral features such as image generation, voice conversation, and extensions
- There is no integration with external storage such as Google Drive; file input is centered on local uploads
- Because it is offered free, future pricing and usage limits are hard to predict
- It is not a foundation model built from scratch but additional training on an open model, so it inherits some characteristics of the base model
- For the latest English-language information or specialized domains, major overseas models may still have the edge
Comparison with Similar Services
| Criteria | Sakana Chat | ChatGPT | Gemini | Claude |
|---|---|---|---|---|
| Provider | Sakana AI (Japan) | OpenAI (US) | Google (US) | Anthropic (US) |
| Strength | Fit for Japanese language and business practices | Breadth of features, image generation | Google product integration, search | Long-context handling, natural writing |
| Web search | Yes | Yes | Yes | Yes |
| Image generation | No | Yes | Yes | No |
| Free access | Free at the time of writing | Free plan available | Free plan available | Free plan available |
Japanese output quality from the major overseas services keeps improving, so it is more useful to compare on how Japan-specific context is handled than on whether Japanese is supported at all.
Who Is It For
- People who want Japanese text that is usable as-is rather than reading like a translation
- People who frequently research or draft documents involving domestic systems and business practices
- People who hesitate to send personal or business documents to overseas services and want to try a domestic option
- Beginners who want to try an AI chat service for free and see how it feels
- Developers considering integrating a Japan-focused model into their own systems in the future
Summary
Sakana Chat is an AI chat service centered on the Japanese language and Japanese business practices. It does not match the major overseas services in sheer breadth of features, but it is a strong option when natural Japanese and domestic context matter most. Since it is free to start, the simplest test is to send the same prompt you normally use and compare how the Japanese output reads. An API version is also available, so there is a path from trial to implementation.