Mahjong School American · NMJL Standard
The National Mah Jongg League Standard

Learn American
MahjongProperly.

One hundred fifty-two tiles. Eight jokers. A mandatory tile exchange called the Charleston. And a card — published fresh every spring — that lists every single hand you are allowed to win with. This is the whole game, explained in plain American English.

152
Tiles in play
8
Jokers
1937
NMJL founded
25–75
Point values
Four players Racks, not hands The annual card is the rulebook Charleston before the first discard
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Who this site is for

Who is this site for? Four kinds of player — find yours and jump straight in.

Start here

American mahjong grew out of the mahjong craze that swept the United States in the 1920s, after Joseph Park Babcock published a simplified rule set for American buyers. Players kept inventing hands, and by the mid-1930s the game had drifted a long way from its Chinese roots.

New to the game? Work through these six steps.

Each step opens a short tutorial. In this order they take you from the tiles to your first real hand.

  1. 1

    Know all your tiles

    The 152-tile set — dots, bams, craks, winds, dragons, flowers and eight jokers.

    Read
  2. 2

    Learn the Charleston passing routine

    The compulsory opening exchange — three passes of three tiles, then the optional second round.

    Read
  3. 3

    Learn how to read the NMJL card

    The card lists every legal hand for the year. Learn what a line is asking for, and what the colours mean.

    Read
  4. 4

    Master Joker wild-card rules

    Jokers fill a group but never a pair or a single — and you can exchange a tile to win one back.

    Read
  5. 5

    Tell closed-hands (C) from open-hands (X)

    An (X) hand may be built by calling discards for exposures. A (C) hand must stay in your rack — the only discard you may claim is the winning tile.

    Read
  6. 6

    Recognize what makes a dead hand

    Wrong tile count, an illegal exposure, a joker used where it cannot go — know what kills a hand.

    Read

Beginner common pitfalls

Most common mistakes new players make — and the rule that fixes each one. Worth a look even if you have played for years.

Quick win resources

Popular free resources — print them, keep them in your tile case, and settle the table before the arguing starts.

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From the school

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