What is Sakana Chat?
Sakana Chat is a free chat assistant from Tokyo-based Sakana AI, opened on 24 March 2026. It is the consumer face of Sakana's models: Namazu, its Japanese-tuned model built on open-weight models from other labs, and since September Fugu Max, its orchestrator that splits a request across a pool of open models. Both answer in Japanese and search the web for current information.
An August update added sandboxed Python, so the assistant can crunch a spreadsheet or build slides and show them in a panel beside the chat, plus image, PDF and Office attachments. Memory arrived in September, and in October My Fish, a screen that shows what it remembers about you, when each memory was used and how memories connect. Sakana Translate lives inside the same app.
The FAQ says the service is free for now, with notice before any price change, and works only from inside Japan. You can chat without an account; signing in saves history and raises the usage cap.
Is Sakana Chat worth it?
Ask most chat assistants for a polite business email in Japanese and you get something that is grammatically fine and socially slightly off: the wrong honorific, a tone that reads as translated.
Sakana Chat is a Japanese company's answer to that. Its Namazu model is post-trained on Sakana's Japanese data for honorifics, business norms and, Sakana says, more neutral answers on political and historical topics. You can switch to Fugu Max for harder multi-step work, or pick a Polite or Osaka-dialect speaking style. It searches the web, runs Python to turn an Excel file into quarterly totals with a chart, and shows the output in a side panel you can download.
The most unusual part is My Fish, added on 15 October. Most assistants with memory keep it out of sight; this one shows you every memory it has stored, when it last used it, which chat it came from and which ones faded after 30 days unused. Small labels in a reply tell you when it learned something new.
The catch: it is a Japanese service for people in Japan, and the terms are written for Sakana's benefit. The FAQ says it only works from inside Japan, your inputs may train Sakana's models unless you opt out, staff may read a small sample, and the terms grant Sakana a perpetual, irrevocable licence to what you enter. You are told not to type anyone's personal information at all. Deleting your history means filling in a contact form, and there is no paid tier with stronger promises.
Our take: for a Japanese speaker in Japan who wants a free second opinion on business Japanese, it earns a bookmark next to ChatGPT. Switch off training in Privacy settings on day one, and keep anything confidential out of it.
Where it earns its place
An office worker at a Tokyo trading company
Draft customer emails in correct keigo
Ask Namazu for a draft with the Polite style selected and check the honorifics. It costs nothing, and signing in keeps the history for reuse.
A sales analyst with a quarterly Excel export
Turn raw rows into quarterly totals and a chart for a meeting
Attach the file and ask for totals; Sakana Chat runs Python in a sandbox and shows the chart in the side panel to download. Strip customer names first, since the terms bar personal information.
A product manager evaluating Sakana's models before buying API access
Compare Namazu and Fugu Max on real Japanese tasks for free
Run the same prompts through both in the model picker, then price the winner on Sakana's API, where Namazu is $0.95 in and $4.00 out per million tokens.
Before you commit
- Setup
- Open chat.sakana.ai in Chrome on a computer or phone from inside Japan; chatting works without registering, and signing in saves history and raises limits.
- Integrations
- No API or connectors in the app; web search, a Python sandbox, image, PDF and Office attachments, and Sakana Translate are built in. The same models are sold separately through Sakana's API.
- Data and privacy
- Sakana's FAQ says your inputs may be used to train its models, and you can opt out under Privacy in settings. Chats and account data are stored on Google Cloud servers in Japan for as long as the account is active, staff may review a small amount of data, and the terms give Sakana a perpetual, irrevocable licence to what you type. Which AI tools train on your data?
- Limits
- Requests are capped per time window, with no figure published; signed-in users rarely hit it, according to the FAQ. Sakana may pause or end the service without notice.
What's good
- Free, with no account needed to start
- Tuned for natural business Japanese and honorifics
- Web search, Python execution and file attachments built in
- My Fish shows exactly what it remembers and when it used it
- Choice of Namazu or Fugu Max
What's not
- Works only from inside Japan
- Trains on your chats unless you opt out
- Terms grant Sakana a perpetual, irrevocable licence to inputs
- No paid or business tier with data guarantees
- History deletion goes through a contact form
Best for
Japanese speakers in Japan who want a free assistant for business Japanese, light data work and current-events questions, and who keep confidential material out of it.
Sakana Chat alternatives
Sakana Chat: common questions
- Is Sakana Chat worth it?
- A capable free Japanese assistant with a rare look inside its own memory, but it only works from Japan and trains on your chats unless you switch that off. We rate it 3.5 out of 5.
- How much does Sakana Chat cost?
- Free for now; Sakana says it will give notice before any pricing change. Signing in raises the usage cap. No paid plans published.
- What are the downsides of Sakana Chat?
- Works only from inside Japan; trains on your chats unless you opt out; terms grant Sakana a perpetual, irrevocable licence to inputs; no paid or business tier with data guarantees; history deletion goes through a contact form.
- Who is Sakana Chat best for?
- Japanese speakers in Japan who want a free assistant for business Japanese, light data work and current-events questions, and who keep confidential material out of it.
- Is Sakana Chat safe for company data?
- Sakana's FAQ says your inputs may be used to train its models, and you can opt out under Privacy in settings. Chats and account data are stored on Google Cloud servers in Japan for as long as the account is active, staff may review a small amount of data, and the terms give Sakana a perpetual, irrevocable licence to what you type.
- What are the best Sakana Chat alternatives?
- The closest alternatives we have reviewed are ChatGPT, Claude, Google Gemini and Sakana Translate.
Answers checked Oct 26, 2026.