American Mahjong Rules

American Mahjong tiles arranged by suits, winds, dragons, flowers, and jokers on a light tabletop

American Mahjong is a four-player tile game built around drawing, discarding, and forming a winning hand that matches a designated pattern on the current National Mah Jongg League (NMJL) card. Although it shares a name with other forms of mahjong, American Mahjong has its own tile set, annual hand card, Charleston exchange, Joker rules, and procedures for declaring Mahjong.

Understanding the rules starts with knowing what makes American Mahjong different: players do not simply collect matching tiles. They work toward a specific hand listed on the current card, follow the rules for exchanging and discarding tiles, and make strategic decisions throughout the round.

This guide explains the core American Mahjong rules, including the tile set, the Charleston, turns and discards, Jokers, exposures, and winning a hand. For a complete beginner walkthrough, see our How to Play American Mahjong guide.

American Mahjong Rules at a Glance

Players: Four players normally play at one table.
The goal: Complete a valid hand that matches one of the hands on the current NMJL card.
The tiles: A standard American Mahjong set contains 152 tiles, with additional tiles depending on the set.
The hand card: Players use the current year’s NMJL card to identify valid winning combinations.
The Charleston: Players exchange selected tiles with other players at the beginning of the game.
Drawing and discarding: Players take turns drawing and discarding tiles as they work toward a valid hand.
Jokers: Jokers can be used in certain combinations, subject to the applicable rules.
Winning: A player declares Mahjong when their hand satisfies the requirements of a valid hand on the card.

These are the basic principles. Exact procedures and exceptions should always be checked against the current rules and the card being used.

1. The American Mahjong Tile Set

American Mahjong uses numbered suit tiles, winds, dragons, flowers, and Jokers. The tiles are used to build combinations that match the patterns printed on the annual hand card.

Suits

The three numbered suits are:

Craks: Numbered tiles in the character suit.
Dots: Numbered tiles represented by circular patterns.
Bams: Numbered tiles represented by bamboo patterns.

Each suit contains numbered tiles from 1 through 9. The numbers and suits matter because a winning hand must match the exact pattern and tile requirements shown on the card.

Winds and Dragons

American Mahjong also uses wind tiles and dragon tiles. These tiles appear in specific combinations on the annual card and are not interchangeable with numbered suit tiles.

The card determines which combinations are valid. Players should check the exact hand requirements rather than assuming that any collection of matching honor tiles will qualify.

Flowers and Jokers

Flowers appear in designated combinations on the card. Jokers may substitute for tiles in certain combinations, but they cannot be used freely in every part of every hand.

Because Joker eligibility and other restrictions affect whether a hand is valid, players should learn the relevant rules before relying on Jokers to complete a combination.

For a closer look at the different tiles, visit our American Mahjong Tiles guide.

2. The Annual NMJL Card

The annual NMJL card is central to American Mahjong. It lists the recognized winning hands for the applicable playing year, along with the tile combinations and other requirements needed to complete each hand.

Players choose a hand from the card and work toward matching it. A hand that looks complete is not necessarily a winning hand: the tile groupings, numbers, suits, and any specified restrictions must match the selected pattern.

How to Read the Card

When choosing a hand, pay attention to:

The exact tile pattern: Check which numbers, suits, winds, dragons, and flowers are required.
The grouping structure: Confirm how the tiles must be grouped and how many tiles are required.
Suit requirements: Some hands require particular suits or combinations of suits.
Joker restrictions: Confirm which groups permit Jokers.
Any special conditions: Read the full hand description before committing to it.

The card changes annually, so players should use the card for the current playing year rather than relying on an old card or a remembered hand.

For official information about the annual card and the League’s materials, visit the National Mah Jongg League.

3. The Charleston: Exchanging Tiles

The Charleston is a distinctive part of American Mahjong. Before regular play begins, players exchange selected tiles with other players according to the applicable Charleston procedure.

The exchange helps players improve their starting hands and decide which combinations may be worth pursuing.

During the Charleston, players must follow the required exchange sequence and any applicable restrictions. The exact procedure should be learned from a reliable rule reference or an experienced instructor, especially when a group is using a particular set of table rules.

Why the Charleston Matters

The Charleston is not simply a random exchange. Players consider which tiles fit their possible hands, which tiles are unlikely to be useful, and whether their starting tiles suggest a promising direction.

However, a promising starting hand is not a guarantee of success. The annual card, subsequent draws, discards, and decisions by other players all affect how a hand develops.

For a more focused explanation, see our What Is the Charleston in American Mahjong? guide.

4. Turns, Drawing, and Discarding

After the Charleston and the required setup, regular play proceeds through turns. Players draw and discard tiles while working toward a valid hand on the annual card.

The basic decision on each turn is whether a newly drawn tile helps the hand enough to keep, or whether another tile should be discarded.

Drawing and Discarding

A player must follow the applicable turn procedure and discard according to the rules. Discarded tiles are visible to the other players and can provide information about the hands being pursued.

A discard is not merely a tile that one player no longer needs. It may be a tile another player can legally claim, depending on the circumstances and the applicable rules.

Claiming a Discard

Some discards can be claimed to complete an eligible combination. A claim must follow the relevant timing, declaration, and exposure requirements.

Not every discarded tile can be claimed for every purpose. Players should understand the specific conditions for making a claim and the procedures that apply when more than one player may have an interest in a discard.

When learning, do not rely solely on informal table habits. Confirm the applicable rules for claims and declarations before playing.

5. Jokers and Valid Combinations

Jokers can be valuable in American Mahjong because they may substitute for tiles in eligible combinations. However, their use is governed by specific restrictions.

The important principle is that a Joker is not a universal substitute for any tile in any situation. Whether it can be used depends on the type of combination and the rules that apply to the hand.

Before Using a Joker

Check the following:

Does the selected hand allow a Joker in the relevant combination?
Does the combination meet the rules for Joker use?
Are there restrictions on how the combination may be completed or exposed?
Does the completed hand still match every requirement on the annual card?

A hand that appears to match the card can still be invalid if a Joker has been used in a prohibited way.

Because these details are important to correct play, consult the current official rules when a specific Joker situation is unclear.

6. Exposed and Concealed Hands

American Mahjong hands can involve different exposure requirements. An exposed combination is made visible to the other players through the applicable declaration and claiming procedure. A concealed hand is subject to the requirements that apply to keeping the hand concealed.

The distinction matters because the selected hand on the annual card may specify conditions that affect whether tiles can be exposed.

Why Exposure Matters

Before claiming a discard or exposing a combination, players should confirm that the action is compatible with the hand they are pursuing.

An exposure can affect a player’s options and may reveal information about their intended hand to the other players. It should therefore be treated as both a rules decision and a strategic decision.

Do not assume that every hand permits the same exposure procedure. Read the relevant hand on the card and follow the applicable rules.

7. Declaring Mahjong

A player declares Mahjong when they believe they have completed a valid winning hand.

Before declaring, the player should confirm that:

The hand matches a pattern on the current annual card.
The required tiles and groupings are correct.
Any suit, number, or other restrictions are satisfied.
Jokers have been used only where permitted.
The hand meets the applicable requirements for winning.

A hand is not valid simply because it contains the expected number of tiles or looks complete. It must satisfy the requirements of the selected hand.

If a declared hand does not meet the applicable rules, the situation must be handled according to the governing rules. Players should not assume that every table uses the same penalty or correction procedure.

8. Scoring and the End of a Round

Scoring in American Mahjong depends on the winning hand and the applicable rules. The annual card provides information relevant to the hands, while the governing rules determine how the result is handled.

Players should establish which rules and scoring procedures they are using before the game begins. This is particularly important for new groups, where players may have learned from different instructors or may be accustomed to different table practices.

If a scoring situation is unclear, consult the applicable official reference rather than relying on memory or assuming that another version of mahjong uses the same procedure.

9. Common American Mahjong Rule Mistakes

New players often make mistakes because American Mahjong combines a changing annual card with specific procedures for exchanging, drawing, discarding, claiming, and exposing tiles.

Watch for these common problems:

Using an outdated card: A hand from a previous year may not be valid on the current card.
Choosing a hand without reading every requirement: Numbers, suits, groupings, and restrictions all matter.
Assuming every combination allows Jokers: Joker use is subject to rules and limitations.
Claiming a discard without following the procedure: Claims must meet the applicable requirements.
Exposing tiles before checking the selected hand: An exposure may not be compatible with every hand.
Treating another mahjong variant’s rules as interchangeable: American Mahjong has its own procedures and conventions.
Assuming a complete-looking hand is automatically valid: The hand must match an eligible pattern on the card.

The best way to avoid these mistakes is to keep the current card available, learn the core procedures, and check uncertain situations against a reliable rule reference.

Frequently Asked Questions

A standard American Mahjong set contains 152 tiles. Some sets include additional Jokers, blanks, or other spare tiles. The exact total can therefore vary by manufacturer and set configuration.

Yes. The NMJL publishes a new card annually. Players should use the card for the applicable playing year and check the complete requirements for the hand they want to make.

No. Joker use is subject to restrictions. Players must check the selected hand and the applicable rules before using a Joker in a combination.

Certain discards can be claimed when the applicable requirements are met. Whether a claim is permitted depends on the situation and the governing rules. Players must follow the required declaration and exposure procedures.

The Charleston is a tile-exchange procedure that takes place before regular play. Players pass selected tiles according to a defined sequence to improve their starting hands.

No. American Mahjong has distinctive features, including the annual NMJL hand card, the Charleston, and its own Joker and gameplay procedures. Rules from another mahjong variant should not automatically be applied to American Mahjong.

Start by learning the tile types, the annual card, the Charleston, and the basic drawing and discarding process. Then practice recognizing valid hands and understanding when claims, Jokers, and exposures are permitted.

For a step-by-step beginner walkthrough, read our How to Play American Mahjong guide.

Continue Learning American Mahjong

Explore these EASTA guides to build your understanding of the game:

American Mahjong becomes easier to understand when the card, the tile combinations, and the procedures are learned together. Use the current card, verify rules when a situation is unclear, and build confidence through practice.