The rules of American Mah Jongg, at a glance

The players and the deal

• Four players: East, the dealer, then South, West and North. Play passes to the right.
• The set: 152 tiles. Bams, Craks and Dots from one to nine, four of each; four of each wind and dragon; eight flowers; eight jokers.
• The deal: East gets 14 tiles and the others 13. The other 99 are the wall.

The Charleston

• The first Charleston, always: each player passes three tiles to the right, then across, then to the left.
• The second Charleston, only if all four want it: three tiles to the left, then across, then to the right.
• A blind pass: on the first pass to the left and the last pass to the right, you may pass on one, two or three of the tiles coming to you without looking at them, with tiles of your own to make three.
• The courtesy pass: then you may exchange up to three tiles with the player across. You both say how many, and you exchange the smaller number.
• Jokers are never passed.

Turns and calls

• East discards first, holding 14 tiles. Then each player in turn draws a tile from the wall and discards one, face up.
• Calling a discard: another player may take it to expose a group on their rack, a pung, kong, quint or sextet, made up with tiles of their own or jokers. Then they discard without drawing, and play goes on to their right, so any players in between miss a turn.
• Not for a single or a pair, except for Mah Jongg: a discard that completes your hand may be called for it.
• Two calls for one discard: Mah Jongg beats an exposure. Between two of the same kind, the player next in turn after the discarder wins.
• Dead discards: a discarded joker can't be called, even for Mah Jongg. Once the wall is empty, the last discard can be called only for Mah Jongg.
• A wall game: when the last tile has been drawn and discarded and no one calls it for Mah Jongg, the game ends with no winner, and no one pays.

Jokers

• A joker stands in for any tile in a group of 3 or more of a kind, never in a single or a pair.
• A joker swap: on your turn, before you discard, you may give a tile from your hand for a joker in any exposure, yours or another player's, when the joker stands for that tile.

Mah Jongg, and dead hands

• Mah Jongg is 14 tiles, on your rack and in your hand, that make one of the hands on the card exactly. Declare it on your turn, or call the discard that completes it.
• Exposures must fit: each group you expose is one of the hand's groups, whole. A hand the card marks C, concealed, has no exposures, though its last tile may be a discard.
• A dead hand: when your exposures fit no hand on the card, your hand is dead. You finish your turn with a discard and play no more, but you still pay the winner.

Payments

Each other player pays the winner. For a hand worth 25 on the card:

• On a discard, its player pays double. Self-drawn, on a tile you drew yourself, all three pay double.
• Jokerless: a hand with no jokers doubles every payment, except a hand of only singles and pairs, which can't use jokers anyway.
• Values on the app's practice card run from 25 to 50. A dead hand still pays, and a wall game pays nothing.