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American Mahjong Rules: The Quick Reference

American Mahjong is played by four players with a 152-tile set, following the hand patterns on the current year's card. This page is the quick reference — the rules a new player asks about most, in the order they come up in a game. It is a summary to play by, not a substitute for the official card and rulebook, which belong on your table.

The card

Winning hands are defined by the annual card: 55 printed rows across 9 sections (the rows expand to 285 concrete hand patterns once tile choices are filled in). You win by completing one of those patterns exactly. Groups of tiles in a hand include singles, pairs, pungs (3 of a kind), kongs (4 of a kind), and quints (5 of a kind).

Dealing and the Charleston

Each player is dealt 13 tiles (East takes 14 and opens). Before play, the table runs the Charleston: two rounds of three-tile passes — Right, Across, Left, then Left, Across, Right — with a vote after the third pass on whether to continue, and an optional courtesy pass across the table before the first discard. (Full walkthrough: How the Charleston Works.)

Turns and calls

Play moves around the table. On your turn you draw a tile, then discard one. Any player may call the most recent discard if it completes a pung, kong, or quint in their hand — or to declare Mahjong. A called set is exposed face-up on your rack, and exposures are final: an exposed set can't be taken back or rearranged.

Two timing courtesies matter:

• A discard can only be called before the next player has drawn and racked (in friendly async play, Mahj & Friends gives a four-hour call window, then the game moves on).
• If nobody at the table can use a discard, play simply continues.

Jokers

Jokers are wild: they can stand in for any tile inside a pung, kong, or quint — but never in a single or a pair. If a joker is sitting in another player's exposed set and you hold the real tile it represents, you may swap them on your turn (joker exchange) and keep the joker.

Winning

Complete a card pattern with 14 tiles and you have Mahjong. Some patterns on the card are marked Concealed: those have to be built with no exposures at all, except calling the winning tile, and each one carries its own point value printed on the card. Finishing an ordinary hand without exposures does not add points by itself. And a win with no jokers at all is the table's favorite kind of story. If the wall runs out first, the hand is a draw and you deal again.

Where the app fits

Mahj & Friends plays by these same rules — NMJL-style, Charleston and courtesy included — but asynchronously: your turn waits in your pocket, and you take it over coffee, at lunch, or on the couch. The built-in Card Reference maps the full card — search it, zoom it, pin up to three hands you're chasing — because checking a hand mid-game shouldn't mean reaching for anything. It is a reference, not the card itself; the paper card still belongs on your table, and the app will happily point you to the National Mah Jongg League for the official one.

Mahj & Friends is not affiliated with the National Mah Jongg League. Hand patterns follow NMJL-style rules.