Ketsuin 結印

Ketsuin is a browser-based typing system that recognizes 12 ninja hand seals through your webcam and converts them to text in real time. Using YOLOX-Nano for gesture detection and T9 predictive logic, it lets you compose words by forming hand signs—similar to old mobile phone T9 input but performed in the air. All processing happens locally in your browser with no data leaving your device.

The app includes a Challenge Mode where you compete globally by performing hand seal sequences as quickly as possible, with ranks from Genin to Six Paths based on speed. It also offers keyboard input as an alternative. The maker built this as a 3-hour experiment to explore real-time gesture-based input in the browser.