Kakuto fighter

A simulated humanoid martial artist, trained with reinforcement learning (PPO) in MuJoCo. It holds a Muay Thai stance, walks and dashes, blocks, and throws 14 techniques: jab, cross, lead and rear hooks, uppercuts, body cross, pull counter, high kicks, knees and elbows.

Try it in your browser: ai.kakuto.io/en/try/. The page runs MuJoCo compiled to WebAssembly and this policy entirely on your device, and downloads the files in web/ from this repository.

How it was trained, with videos and costs: ai.kakuto.io.

This model

Checkpoint	distill9-196.6M (196.6 M environment steps)
What it is	A student policy distilled from per-skill teacher policies
Body	muscular-fast: 48 actuators
Network	MLP, 2 hidden layers of 512 units, ELU; 465 observations in, 48 actions out

Files

Everything the browser demo needs is in web/:

File	What
fighter.xml	The MuJoCo model (MJCF): the fighter's body and the scene
fighter.json	The metadata: tensor layout in fighter.bin, observation layout, action scaling, techniques
fighter.bin	The policy's weights and observation normalisation, plus the stance tables
punches.bin.gz	The techniques' reference tables (loaded when the first technique is used)
walk.bin.gz	The walking reference tables
mujoco-3.16.0.wasm.gz	MuJoCo 3.16.0's WebAssembly engine, gzipped; unchanged from the @mujoco/mujoco npm package
MUJOCO_LICENSE	MuJoCo's licence (Apache 2.0)

The observation is built by the environment code on the demo page, so the weights alone do not reproduce the behaviour.

Licence

The fighter's model, weights and tables are © 2026 Kakuto Technology GK, under CC BY 4.0: you may use, share and adapt them for any purpose, including commercially, as long as you credit Kakuto with a link to kakuto.io wherever they are used, e.g. on the page or screen that uses the model, or in your credits or about page:

Fighter model by Kakuto (https://kakuto.io)

In a website or app, make "Kakuto" or the address a link to https://kakuto.io. If you changed the files, say so ("Based on the fighter model by Kakuto (https://kakuto.io), modified"). Full terms: LICENSE.

To cite it:

@misc{kakuto_fighter_2026,
  author       = {{Kakuto Technology GK}},
  title        = {Kakuto fighter},
  year         = {2026},
  howpublished = {\url{https://huggingface.co/kakuto-io/fighter}},
  note         = {https://kakuto.io}
}

MuJoCo's engine (web/mujoco-3.16.0.wasm.gz) is not covered: it is © DeepMind Technologies Limited, under the Apache License 2.0 (web/MUJOCO_LICENSE).