Ketsuin is a web-based input method that lets you type text using ninja hand signs detected through your webcam. Powered by YOLOX-Nano object detection and T9 predictive text logic, it recognizes 12 ancient hand seals and converts them into characters in real time.
Point your webcam at your hands and form one of the 12 ninja seals. The AI model detects each sign and maps it to a T9 key group. Combine signs to spell words, just like typing on an old mobile phone — but with your hands in the air.
| Key | Sign | Kanji | Letters |
|---|---|---|---|
| 1 | Rat | 子 | .,?! |
| 2 | Ox | 丑 | ABC |
| 3 | Tiger | 寅 | DEF |
| 4 | Hare | 卯 | GHI |
| 5 | Dragon | 辰 | JKL |
| 6 | Snake | 巳 | MNO |
| 7 | Horse | 午 | PQRS |
| 8 | Ram | 未 | TUV |
| 9 | Monkey | 申 | WXYZ |
| 0 | Dog (Space) | 戌 | SPC |
| * | Bird (Delete) | 酉 | DEL |
| # | Boar (Next) | 亥 | NEXT |
Test your hand sign speed against other ninjas worldwide. Choose a jutsu, perform the hand seal sequence as fast as possible, and compete on the global leaderboard. Ranks range from Genin (rookie) to Six Paths (godlike speed).
Yes, for hand sign detection mode. You can also use keyboard keys 1-9 as an alternative input method.
YOLOX-Nano for hand sign detection, ONNX Runtime WebAssembly for inference in the browser, and a T9 engine for predictive text input. No data leaves your device.
Yes, completely free and open source.