Riichi Companion

A mobile-first Progressive Web App for Riichi Mahjong players. Installable from the browser, works offline, no account required.

Read the story behind its creation here.

Hand Analyzer

• Visual tile picker or text notation (123m456p789s11z)
• Shanten count and tenpai waits with remaining tile count and wait type
• Score calculation: han, fu, points, fu breakdown, yaku list
• Furiten detection and discard tracker
• Learning mode to hide waits until you're ready
• Practice mode — guess the waits on a random tenpai hand before revealing

Game Tracker

• 3-player (Sanma) and 4-player (Yonma), Hanchan and Tonpuusen
• EMA ruleset — open tanyao, uma, tenpai payments, chombo
• Dice rollers with full wall diagram: break position, dead wall, and dora indicator
• Riichi pool tracking, snapshot undo, score projection with bubble warnings
• False tenpai chombo, multi-ron hand entry, furiten warning on ron calls
• End-of-game summary with shareable text export and JSON download

Game History

• Past games saved locally — browse placements, hand logs, and share summaries

Source code on GitHub. Open the full app at tomaranai.pro/riichi-companion/ to install it as a PWA from your browser.