| Hand size | 13 tiles |
|---|---|
| Winning shape | A line printed on the card |
| Wall | 152 tiles, including eight jokers |
| Scoring | The value printed beside your line |
| Signature | The Charleston, and the joker exchange |
American Mah Jongg is the outlier, and the one most likely to confuse a player who learned anywhere else. You are not building runs and triplets freely — you are building one specific hand printed on a card, and if your tiles don't match a line on that card, you cannot win with them.
The wall is 152 tiles rather than 136, because it includes eight jokers. Flowers are ordinary hand tiles here, not bonuses: nothing is set aside, nothing is replaced. Hands are 13 tiles.
The card
Each line on the card is a pattern — groups of matching numbers, runs, winds, dragons — with a point value beside it and conditions attached: this suit or any suit, concealed or exposed. Choosing which line to chase, and knowing when your line has died, is the entire game. It is closer to a puzzle than to the tile-reading of the Chinese games.
The card is licensed material and is not reproduced in the app. More Mahjong ships a self-authored practice card in the same format, so the mechanics — matching, exposing, jokers, scoring — all play exactly as they should.
The Charleston
Before play, tiles move around the table in a fixed sequence: three right, three across, three left — that third pass blind, meaning you pass tiles you haven't seen. Then, if all four players agree, a second set of three. Then a courtesy pass of nought to three tiles across, exchanged at the lower of the two offers.
It is the most social ritual in any mahjong variant, and it is where a hopeless deal becomes playable.
Jokers
Jokers are wild, but not everywhere. A joker can stand in within a group of three or more identical tiles — never in a pair, never in a single, never in a mixed run. That single rule is why Singles and Pairs hands are jokerless by construction, and why hoarding jokers is not automatically correct.
You can also exchange for one: on your turn, swap a real tile into an exposed group where a joker is doing that tile's job, and take the joker.
What the app enforces
- Only card-legal wins, matched against the whole card
- Exposures that map onto whole uniform groups, jokers included
- Jokers wild in groups of three or more identical tiles, and nowhere else
- All seven Charleston passes, the blind pass, the vote, and the courtesy exchange
- The joker exchange, on your turn only
- Kongs that draw no replacement tile — an American rule that trips up everyone else
- East breaking her own wall
The Card page shows the closest line to your hand tile by tile — what you hold, what you still need, and which jokers are doing work — and folds away the lines your exposures have already killed.
