Japanese AI startup Sakana AI announced on July 6th that it has added a free translation feature called “Sakana Translate” to its conversational service “Sakana Chat.” This tool supports bidirectional translation between Japanese, English, and Chinese, with its key feature being the ability to translate business honorifics and internet slang along with context and the sense of distance between conversation participants, rather than simple word-for-word replacement. Users can access it for free by simply registering an account, and it is currently available as a web application.
Sakana AI Releases Free Translation Tool ‘Sakana Translate’, Featuring Deep Japanese-Style Translation
Three main features: translation, polishing and proofreading, and answering questions
Sakana Translate comes with three core features. The translation mode supports long-text input of up to approximately 5,000 characters, with translations displayed in real-time streaming—ideal for handling various types of text content including emails, documents, articles, and web pages. Translation history is automatically saved for easy reference later.
The polishing and proofreading mode adjusts input text to more appropriate expressions. It not only corrects grammar but also fine-tunes naturalness, politeness, tone, and the sense of distance with the recipient. Changes are displayed using difference highlighting, allowing users to intuitively confirm the modifications. This feature is particularly suitable for quality checking English business emails, serving as a writing assistant. For users who frequently write Japanese or English business emails, this is essentially having both a translation tool and a writing assistant at the same time.
The questioning mode lets users ask follow-up questions about translations or refinements directly on the same screen—whether to confirm nuances, suggest alternative expressions, or explain grammar and word choices. This removes the hassle of toggling between translation tools, dictionaries, and search engines, integrating the translation and learning process into a single interface.
Namazu Translation Engine and Benchmark Performance
The translation engine uses Sakana AI’s own model series “Namazu,” which takes overseas frontier models and fine-tunes them through post-training to create exclusive models tailored for the Japanese market. Sakana AI’s concept is defined as “deep translation of Japanese”—their goal is not just replacing words and sentence structures, but also conveying the context, tone, and sense of interpersonal distance behind the text.
In translation quality evaluation, Sakana AI used the evaluation data from the WMT 2024 General Translation task, measured with the automatic evaluation metric XCOMET-XL. The results show that Sakana Translate scored 0.835, ranking just below Google Gemini 3.1 Pro (0.851) and OpenAI GPT-5.5 (0.843), while surpassing Anthropic Claude Opus 4.7 (0.831).
In other words, this free translation tool from the Japanese startup has already surpassed Anthropic’s most powerful model, Claude Opus 4.7, on automated benchmarks, trailing only behind the latest models from Google and OpenAI. Given that Sakana AI is far smaller than tech giants like Google and OpenAI, this achievement is quite remarkable. Sakana AI itself has been低调 about it, saying it is “close behind the leading models,” but the scores show that Namazu has established clear competitiveness in Japanese translation.
Real translation examples: from business formal language to internet slang
Sakana AI’s official blog provides concrete translation examples to demonstrate its linguistic nuance handling capabilities. In a Japanese-to-English business email scenario, the original text 「お見積り拝見しました。勝手なお願いですが、もう少しご相談できますか？」was translated as 「I saw your quote. This is a bit of a selfish request, but could we talk a bit more?」, preserving the polite tone and professional distance of the original. Such fixed expressions in Japanese business keigo are often only literally translated by traditional tools, making it difficult to convey subtle cultural nuances like “sorry to bother you” or “I’m making an unreasonable request.”
In the context of translating English internet slang to Japanese, the original text “Iykyk, honestly. It’s an inside joke from the group chat.” was rendered as “まあ、わかる人にはわかるよね。グループチャットの内輪ネタだから。”, converting internet abbreviations like “Iykyk (If you know, you know)” into expressions with the same warmth in casual Japanese. When traditional translation tools encounter such internet slang, they often translate it literally as “If you know, you know,” which sounds rigid and unnatural.
Additionally, Sakana Translate offers multiple tone conversion options including “casual,” “polite,” “concise,” “native-sounding,” and “Osaka dialect,” allowing users to switch the style of their translation results with one click.
Free to use, with plans to enter the enterprise market
Sakana Translate is currently available for free, with users only needing to register an account to access all features including translation, proofreading, and Q&A. This free plan is quite appealing for individual users and small teams, especially those who frequently handle Japanese business communications or translate Japanese documents. Sakana AI has unveiled its future development roadmap, with plans to roll out industry-specific optimized translation engines, file translation features, and glossary integration. Additionally, the company will release an API for developers to integrate, and support SSO, audit logs, and on-premises deployment, officially entering the enterprise market.
For Taiwanese users, Sakana Translate supports bidirectional Chinese translation and emphasizes deep processing of Japanese nuance. For users who need to frequently handle Japanese business communication, translate Japanese technical documents, or understand Japanese internet culture content, it is a new tool worth paying attention to. Alongside existing translation services like Google Translate, DeepL, and ChatGPT Translate, Sakana Translate positions itself with “deep translation of Japanese nuance” as its differentiation, providing another option in the translation market.