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American Mah Jongg Rules Companion

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American Mah Jongg is governed by a consistent set of rules that apply across home games, clubs, and tournaments in the United States. While the hands listed on the NMJL card change each year, the rules that govern how tiles are handled, grouped, exposed, and declared do not.
 

This Rules Companion explains the core rules of play that determine whether a hand is valid or dead under NMJL standards.
 

Basic Requirements for a Valid Hand

To declare Mah Jongg, a hand must meet all of the following conditions:

  • The hand contains exactly 14 tiles

  • The tiles match one complete line on the current NMJL card

  • All tiles are used exactly as shown on that line

  • Jokers are used only where permitted

  • Exposures, if any, follow NMJL rules
     

If any of these conditions are not met, the hand is not valid.
 

Tile Count Rules

  • Players are dealt 13 tiles

  • The dealer begins with 14 tiles

  • On each turn, a player must draw one tile and discard one tile

  • A player must always maintain the correct tile count on the rack
     

A hand with too many or too few tiles cannot be valid.


Rules for Calling Tiles

A player may call a discarded tile only when all of the following are true:

  • The tile completes a Pung, Kong, Quint, or Sextet

  • The hand is not marked Concealed on the NMJL card

  • The call completes a grouping exactly as shown on the card
     

Tiles may not be called to complete:

  • Singles

  • Pairs
     

When a tile is called:

  • The completed grouping must be exposed immediately

  • The player takes the next turn

  • One tile must be discarded
     

Calling a tile incorrectly results in a dead hand.
 

Exposed vs. Concealed Hands

Some hands on the NMJL card are marked Concealed.
 

Concealed Hand Rules:

  • All tiles must be drawn from the wall

  • No tiles may be called

  • Tiles remain hidden until Mah Jongg is declared
     

If a concealed hand is exposed at any point, the hand becomes dead.
 

Exposed Hand Rules:

  • Tiles may be called where permitted

  • Completed groupings are displayed face-up on the rack

  • Exposures must match the hand on the card
     

Rules for Jokers

American Mah Jongg is based on 8 Jokers.

Jokers may be used to replace any tile (Numeral, Wind, Dragon, or Flower) only when that tile is part of:

  • a Pung

  • a Kong

  • a Quint

  • a Sextet
     

Jokers may not be used in:

  • Singles

  • Pairs
     

Using a Joker where it is not permitted makes the hand dead.
 

Joker Exchange Rules

A player may exchange a natural tile for a Joker in another player’s exposed grouping if:

  • The player has the exact natural tile being replaced

  • The exchange is made during the player’s own turn

  • The exchange does not expose the exchanging player’s hand
     

Only one Joker may be exchanged at a time.
 

Rules for Flowers, Winds, and Dragons

  • Flowers are suitless tiles and are used only as shown on the card

  • Winds (North, South, East, West) are suitless and form their own groupings

  • Dragons (Red, Green, White) are used according to the card’s instructions
     

When White Dragons are used as zeroes on year-based hands, they are suitless.

In other cases, Dragons follow the suit relationships specified on the card.
 

Suit Rules

American Mah Jongg uses three suits:

  • Bams

  • Craks

  • Dots
     

When the NMJL card shows:

  • One color → one suit is used

  • Multiple colors → multiple suits are required
     

Card colors indicate how many suits, not which suits.
 

Dead Hand Rules

A hand becomes dead when it can no longer legally match any complete line on the NMJL card.
 

Common causes include:

  • Illegal exposure

  • Illegal call

  • Using a Joker in a Single or Pair

  • Exposing a concealed hand

  • Changing direction mid-hand so no card line matches
     

A dead hand:

  • Remains at the table

  • Continues discarding

  • May not declare Mah Jongg
     

Declaring Mah Jongg

A player may declare Mah Jongg only when:

  • The hand contains 14 tiles

  • The tiles match one complete card line

  • All rules regarding Jokers and exposures are followed
     

Once declared, the hand is verified before the game ends.
 

Quick Summary

American Mah Jongg rules govern how tiles are drawn, grouped, exposed, and declared. While the NMJL card changes each year, the rules for legality remain consistent. A valid hand must always contain 14 tiles and match one complete line on the current card.
 

Published by the American Mah Jongg Association — the trusted home for American Mah Jongg players.

Related resources: Glossary • Rules • How to Read the NMJL Card • FAQ • Questions

 

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