Mahjong Book: Learn Riichi

Learn riichi rules, scoring and tile efficiency. Play 3D AI or online matches.

Mahjong Book brings learning, scoring and playing Japanese riichi mahjong together.

LEARN THE TILES
Explore tile types, winning shapes, waits, yaku, dora, fu and scoring through tile-based lessons and quizzes. Spaced repetition helps you review. Look up a yaku or unfamiliar term in the built-in references.

EXPLORE TILE EFFICIENCY
Chapter VII covers shanten, ukeire, visible tiles and lookahead. The on-device lab compares every discard in a closed 14-tile hand over your next two draws. Generate exercises or enter your own tiles. It compares a stated structural target, not real-game win rates, value or defense.

ENJOY THE MUSIC
Listen to all 19 bundled tracks in the Music Library, with seeking, repeat and shuffle. No streaming connection is needed.

PUT IT INTO PLAY
Play 4-player or 3-player mahjong on a 3D table against beginner, intermediate or advanced AI. Tap a tile to select it, then tap it again to discard. Practise what you learn, one decision at a time.

UNDERSTAND THE SCORE
In Scoring Training, winning hands from AI matches become fu and scoring questions. See the explanation whether your answer is right or wrong. The hand payment, honba bonuses and riichi deposits are shown separately, so you can follow how the final total is formed.

PLAY WITH FRIENDS OR THE WORLD
Join a worldwide table or create a private room with a 4-digit code. Worldwide tables fill empty seats with AI two minutes after recruitment starts. Chat is limited to preset phrases shared within the same room; there is no free-text chat. Online play requires an internet connection.

SWITCH THE APP TO ENGLISH
The in-app language button lets you switch between English and Japanese at any time. Lessons and AI matches work offline.

One-time purchase. No ads, no in-app purchases and no gambling.

--- 日本語 ---
「麻雀の書」は、牌・役・符計算を学ぶ講座とクイズ、四人打ち・三人打ちの3D対局を一つにしたリーチ麻雀アプリです。初級・中級・上級AIとのオフライン対局、世界対戦、4桁コードで集まるプライベート対戦に対応。符計算修行では、手牌の点数と本場・供託を分けて解説します。

アプリ内の言語ボタンで日本語／Englishを切り替えられます。オンライン機能にはインターネット接続が必要です。広告なし・追加課金なし・賭博要素なし。