Hand Score Simulator
Japanese Riichi Mahjong — Modern riichi / yonma, one of the 66 rulesets in the tree, scored under the European Mahjong Association’s Riichi Rules 2025.
points
How to use it
A finished winning hand is dealt every time you open the page. Read it left to right: the concealed tiles first, then the tile the hand was won on, set a little apart, then any sets claimed off another player’s discard, with the claimed tile lying on its side to show who it came from. Past the vertical rule are the indicators that were turned over — the dora indicator always, and the under-dora indicator as well when the hand declared riichi. An indicator does not name itself: the dora is the next tile along, nine wrapping to one, North to East and Red Dragon to White. The dora tiles in the hand glint every few seconds.
Under the board are the facts you cannot read off the tiles: the winds, whether the hand was won by self-draw or off a discard, and how much of it was claimed. Everything the score depends on is shown before the score.
Practising against it
Tick Hide the score until I ask for it and the whole hand stays in view while the yaku, the fu and the payment are held back behind a button. Work the hand out, then press it and check yourself against the breakdown. It is shown line by line, along with who pays what, since the winner may be paid by one player or by all three.
Tick Time how long I take as well and the clock runs from the deal until you ask for the score. Deal another hand draws a fresh one at any point.
The tile artwork is FluffyStuff’s riichi tile set, released into the public domain under CC0.
The rules are the European Mahjong Association’s Riichi Rules 2025. The code that deals and scores this hand was written by an AI model from them, and is not itself a source: where a score here disagrees with the rulebook, the rulebook is right.