Riichi Mahjong
Japanese riichi mahjong with yaku, dora and three AI levels
Japanese riichi mahjong in the browser, with standard online-style rules, a three-player mode, beginner hints and four-player online rooms.
Features
Standard riichi rules
Hanchan or East-only, red fives, open tanyao, ippatsu, ura dora, double ron and abortive draws.
Learn as you play
Shanten count, waits and tiles left, a furiten warning and a suggested discard.
Four-player online
Quick match plays East-only; private rooms let the host fill seats with the computer.
Three-player sanma
A separate three-player mode with no 2m to 8m, no chi and North as bonus dora.
How it works
- 1
Draw and discard
Draw one tile from the wall and discard one, always keeping 13 in hand.
- 2
Build toward a yaku
Aim for four sets and a pair that includes at least one scoring pattern, such as tanyao or yakuhai.
- 3
Riichi and win
Declare riichi with a closed ready hand, then win by tsumo or ron while the han and fu are counted for you.
About the game
Riichi Mahjong is the Japanese style, played with 136 tiles and no flowers. Four players start with 25,000 points and keep a 13-tile hand. What sets it apart is the yaku requirement: a hand of four sets and a pair is not enough on its own, it must also contain at least one scoring pattern. Declaring riichi on a closed ready hand is itself a yaku, which is why the game takes its name from it. Points are calculated from han and fu, dora tiles add han, and the furiten rule stops you from winning by ron on a tile you threw away earlier.
What Seriauth built
The site follows the ruleset most players know from popular online clients: hanchan or East-only games, red fives, open tanyao, ippatsu, ura and kan dora, double ron, uma and counted yakuman, with options you can change. A three-player mode follows the common online sanma rules, with North set aside as bonus dora.
Each of the three AI levels has its own style. Easy never folds; Normal calls only with a yaku and folds against riichi; Hard weighs danger using suji, walls and dora. For learners, the table shows shanten, waits, remaining tiles and a suggested discard, and a yaku list is one tap away. A beginner guide and pages for individual yaku cover the theory. Four-player online rooms add quick matching and private tables, and a disconnected player is replaced by the computer.
FAQ
What makes riichi different from other mahjong?
Every win needs at least one yaku, there are no flowers, and points come from han and fu, with dora adding han.
What is furiten?
You cannot win by ron on a tile you have already discarded. The game warns you when your hand is in furiten.
Can I play with only three players?
Yes. The site includes three-player riichi (sanma) against two computer opponents.
Is my game saved?
Yes. The current game is saved automatically on your device so you can come back later.
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