Sakana AI

A Tokyo research company

Sakana AI is a research and development company based in Tokyo, founded in July 2023.^[1] Its registered name is Sakana AI K.K. and its headquarters is in the Azabudai Hills Mori JP Tower in Minato-ku, Tokyo.^[1] The company's own overview splits its work into research output, a product line and a family of Japanese-language models.^[1]

Founders and leadership

The three founders hold the top roles: David Ha is chief executive, Ren Ito is chairman and Llion Jones is chief technology officer.^[1] Jürgen Schmidhuber serves as chief scientific advisor and works with the company's RSI Lab on recursive self-improvement and physical AI.^[1] Recursive self-improvement here means AI systems taking part in building the next generation of AI systems; physical AI means models that act through robots and other hardware rather than only in software. Ai Fujiki is chief financial officer; she joined in July 2025 as head of corporate planning after about ten years at Goldman Sachs.^[1]

Research: merging models instead of training them

The company lists The AI Scientist, the Darwin Gödel Machine, ShinkaEvolve and AB-MCTS among its research output.^[1] The line of work its public materials describe in most detail is model merging: rather than training one large model from scratch, take several open models that already exist and combine them into a single model.

On 19 March 2024 Sakana posted the paper behind EvoLLM-JP, which describes an evolutionary search over combinations of open models and presents the method as working without extra training data or compute.^[2] The released 7B model merges Shisa Gamma 7B v1, WizardMath 7B v1.1 and Abel 7B 002, and its weights went up on 6 March 2024.^[3]

Merging is interesting because open models tend to be good at different things: they were trained on different data with different objectives, so their strengths are complementary. The basic operation is to average or otherwise mix their weights in the hope that the result inherits strengths from several of them. Evolutionary search turns this into a search problem: instead of knowing in advance which models to combine and in what proportion, generate many combinations, score them, keep the better ones and recombine those into the next generation.

Products

The product line includes Sakana Chat, Sakana Marlin and Sakana Fugu, while the Japanese models are named Namazu.^[1] The overview lists the products and the Japanese models separately, so they read as two distinct lines rather than one.^[1]

Investors

The company's latest disclosed round is a Series B. Japanese investors listed include ITOCHU, ANA, KDDI, NEC, Fujitsu, MUFG and Mizuho, and overseas investors listed include Google, NVIDIA, Khosla Ventures, NEA, Lux Capital, Salesforce Ventures and In-Q-Tel.^[1] The list spans trading houses, an airline, telecom and electronics manufacturers and banks alongside corporate and venture investors from abroad — broad coverage for a young company.

Where it sits

Sakana AI is a young company that both publishes research and ships products under its own name, with Japanese-language models on a separate line.^[1] Judging by the projects it lists, its research leans toward getting more out of models that already exist and toward automating parts of research itself, and its RSI Lab works on recursive self-improvement.^[1] The Series B shows interest from both Japanese industry and overseas technology investors.^[1]