American Mahjong (NMJL) Rules

What American mahjong actually is

American mahjong, standardised by the National Mah Jongg League (NMJL), is structurally different from every other style on this site. You do not memorise a scoring table. You do not count fan. You buy a card once a year, and that card lists every hand that is legal for the next twelve months.

This single design choice explains almost every rule that follows. Because the legal hands change annually, the game stays fresh for regular players and stays closed to anyone playing from memory. It also means a hand that looks perfect at the table can still be refused — the pattern is not on this year's card.

The card decides what a win is

The NMJL card is printed and sold as a physical card each year; the 2026 edition follows the same layout as recent years, with patterns arranged in numbered sections and a small code beside each one. A hand is legal only if it matches a line on the card exactly: same tile counts, same suits, same use of dragons and winds, same treatment of Jokers.

Two practical consequences:

• Learn the card, not the rules. Experienced players spend the first ten minutes of a session reading the card and picking three or four patterns to chase.
• Call the pattern when you declare. In most clubs you name the line you are claiming, which is how the table checks your hand without recounting it tile by tile.

The set: 152 tiles and eight Jokers

American mahjong uses the standard 144 tiles plus eight Jokers, for 152. Some sets also include four blank spare tiles and a set of scorecards, neither of which is used in play. The Jokers are the only tiles whose value is not fixed at the start of the hand.

Component	Count	Role
Suited tiles (three suits, 1 to 9)	108	Identical to other styles
Winds and dragons	28	Used inside card patterns
Flowers	8	Present in the set, rarely used in play
Jokers	8	Substitutes, with strict limits
Total	152	The largest standard set in common use

Charleston: the compulsory opening pass

After the deal, before any tile is discarded, every player passes tiles to the left, then across, then to the right. Three tiles per pass, three passes. This is the Charleston, and it is not optional.

1. First pass: three tiles to the player on your left.
2. Second pass: three tiles to the player opposite you.
3. Third pass: three tiles to the player on your right.

After the third pass the dealer may offer a second Charleston. It is optional, most clubs play one, and the table should agree on it before the first tile is dealt. The Charleston converts dead tiles into ones your chosen pattern needs, which is why reading the card before the deal matters more here than anywhere else.

Claims: pung and kong, never chow

You may claim a discard to make a pung (three identical) or a kong (four identical). You may not claim a discard to complete a run, because runs are not a legal unit in American mahjong scoring — the card describes hands in terms of pairs, pungs, kongs and quints, not sequences.

That prohibition has a second effect: because nobody can chow, discards are far safer than in Chinese styles. A tile that would be dangerous in Hong Kong mahjong is often dead in American play. Defence therefore leans almost entirely on reading which patterns other players have announced or are visibly building.

How Jokers may be used

Jokers substitute for tiles, but only in narrow circumstances. The standard rule is that a Joker may stand in for a tile in a group of three or more identical tiles; it may not fill a pair, a single tile, or a run.

Situation	Joker allowed?	Why
Third tile of a pung	Yes	Group of three identical tiles
Fourth tile of a kong	Yes	Group of four identical tiles
A pair used as the eyes	No	Pairs must be genuine
A single tile in a pattern	No	No group to substitute into
A tile in a run	Not applicable	Runs are not scored units here

Some house rules also treat the white dragon as a limited wild tile ("soap"), which may substitute only for suited tiles. That is a regional refinement, not part of the base card, so confirm it before the first hand.

Scoring works from the card

Each line on the card carries a value, printed as a number of points or as a multiple of the table stake. There is no fan, fu or tai arithmetic to perform: you match the pattern, you take its value, and the payment rules of the table decide who pays what.

Two habits keep scoring honest:

• Declare the line number when you win, not just "mahjong".
• Check the Joker count before declaring. A pattern that caps Jokers at one, or bans them entirely, fails if you've used two.

Where beginners lose hands

1. Chasing last year's pattern. The card is replaced annually; a hand from memory is usually illegal.
2. Using a Joker as a pair. The most common false declaration in the game.
3. Skipping the Charleston. Passing is compulsory; the hand is not played until all three passes are done.
4. Assuming chow is available. It is not, in any NMJL-sanctioned play.

If you are coming from Hong Kong or riichi mahjong, the mental shift is this: stop thinking about what your tiles could become, and start thinking about which printed line they are closest to.

Quick answers

Can you chow in American mahjong?

No. Only pung and kong may be claimed from a discard. Runs are not part of the scoring vocabulary, so there is nothing to claim.

How many Jokers are in an American mahjong set?

Eight. They bring the total to 152 tiles, which is the largest standard set used in any common mahjong style.

Is the Charleston mandatory?

The first three passes — left, across, right — are compulsory. A second Charleston is optional and depends on the table agreeing to it before play.

Why was my complete hand rejected?

Because American mahjong accepts only the exact patterns printed on the current year's card. A structurally valid hand that is not on the card is not a win.