American mahjong rules: the complete reference

These are the standard National Mah Jongg League (NMJL) rules as commonly taught. The League's own rulebook and the back of each year's card are the final word, and many groups play house rules on top. Agree on any variations before the first hand.

The goal

Be the first to complete one of the hands printed on the current year's card, exactly as printed, and declare "Mah Jongg". A winning hand has 14 tiles. Each player needs their own copy of the card.

Equipment

A set with 152 playing tiles: 108 suit tiles, 16 winds, 12 dragons, 8 flowers, 8 jokers. What each tile is.
Four racks, ideally with pushers, two dice, and a current card for each player.
Four players. There are official ways to play with three or two.

Setup

Shuffle the tiles face down. Each player builds a wall 19 tiles long and two high.
Roll for East (the dealer). East rolls again to choose where the wall is broken.
Players take tiles in turn, four at a time, until East has 14 tiles and everyone else has 13.

Setup and dealing, step by step.

The Charleston

First Charleston, required: pass 3 tiles right, 3 across, 3 left.
Second Charleston, optional: left, across, right. Any one player can stop it.
Blind pass: on the last pass of each Charleston (first left, second right) you may pass on 1, 2 or 3 of the tiles coming to you without looking, so you still pass three in total.
Courtesy pass: optional, 0 to 3 tiles with the player across, by agreement.
Never pass a joker.

The Charleston in detail, or practise it.

Turns

East discards first. Play then moves to the right (counter-clockwise).
On your turn, take the next tile from the wall, then discard one face up and name it out loud.
You always have 13 tiles after you discard.

Calling a discard

Any player can call the latest discard, in or out of turn, but only:

to complete a pung (3), kong (4), quint (5) or sextet (6), which must then be exposed; or
to win, if that tile completes the hand. This is the only time you can call for a single tile or a pair.

Call promptly, before the next player takes a tile from the wall. If two players want the same discard, a call for Mah Jongg beats a call for an exposure. Between two calls of the same kind, the player next in turn after the discarder usually wins. After calling and exposing, you discard and play continues to your right, so anyone in between loses their turn.

A discarded joker can never be called.

Exposures

An exposure is a group you have called and laid face up on top of your rack. Everyone can see it.
Hands marked C (concealed) on the card cannot have any exposures. You may only call the final winning tile.
Hands marked X (exposed) may include exposures.
Once a group is exposed it stays on your rack. If your exposures no longer fit any hand on the card, your hand is dead.

Joker rules

Jokers substitute for any tile in a group of three or more identical tiles.
Never in a pair, never as a single tile, never in singles-and-pairs hands.
Never passed in the Charleston.
Redeeming a joker: on your turn, if any exposure holds a joker standing in for a tile you have, you can swap your tile for the joker. You can do it more than once per turn. You cannot use a discard to do it.
A discarded joker is dead and cannot be picked up.

Joker rules in full.

Declaring Mah Jongg

Your 14 tiles, concealed and exposed together, must match one hand on the card exactly.
Say "Mah Jongg", then lay out the whole hand. Nobody should throw in their tiles until the hand has been checked.
If you declare Mah Jongg by mistake and the hand cannot be fixed, it is dead. Players who have not exposed their racks keep playing.

Dead hands and wall games

Dead hand: your exposures cannot make any hand on the card, you have the wrong number of tiles, or you declared Mah Jongg in error. You stop trying to win but keep drawing and discarding until the game ends.
Wall game: the wall runs out with no winner. Nobody pays.

Paying

How the hand was won	Payment
On a discard	Discarder pays double the hand's value; the other two pay its value
Self-drawn (picked from the wall)	All three pay double
No jokers in the hand	Doubles the payment again. Singles-and-pairs hands, which never use jokers, are commonly excluded.

Scoring, with worked examples.

Rule questions, including “can you…?”

Can you use a joker in a pair?

No. Jokers can only be used in groups of three or more identical tiles: pungs, kongs, quints and sextets. They can never be part of a pair or stand alone as a single tile.

Can you use a joker for a single tile, like a single flower or a NEWS hand?

No. A joker can never stand in for a single tile, so it cannot be used in NEWS, in a single dragon, or in any singles-and-pairs hand.

Can you discard a joker?

Yes, at any time. A discarded joker is dead: nobody can call it, not even for Mah Jongg.

Can you call a discard for a pair?

Only if it is the last tile you need to win. Otherwise you can only call a discard to complete a group of three or more.

Can you call a discard for a run (consecutive numbers)?

Not to make a run on its own. American hands are built from groups of identical tiles, singles and pairs; you call a discard to complete a pung, kong or quint, or for the tile that wins.

Can you call a flower?

Yes, for a pung, kong or quint of flowers, or for Mah Jongg. A single flower or a pair of flowers can only be called if it wins the game.

Can you swap a joker with a discarded tile?

No. To redeem a joker from an exposure you must use a matching tile from your own rack, on your own turn.

Can you play American mahjong without a card?

Not by the official rules. You can only win with a hand on the current year's card, so every player needs one. While learning, some groups share a card or use a free practice card.

What happens if nobody wins?

If the wall runs out and no one declares Mah Jongg, it is a wall game. Nobody pays, the tiles are reshuffled and the deal moves on.

How many tiles do you start with?

Thirteen, except East, who starts with 14 and discards first.

Which direction does play go?

To the right, which is counter-clockwise.

Can more than four people play?

Only four play each hand. With five, players commonly take turns sitting out.

Can you change your mind after calling a tile?

Groups differ, but once you have exposed the tiles, the exposure usually stands. Be sure before you call.

What if someone declares Mah Jongg by mistake?

If the hand cannot be fixed, it is dead. Players who have not exposed their own racks keep playing.

Want these rules on one page by your elbow? Print the cheat sheet.

Sources: Wikipedia: American mahjong; The Mahjong Line, American Mahjong 101 (joker and calling rules); Tom Sloper on NMJL payment rules.