American mahjong jokers: the rules

Jokers are what make American mahjong American. They're also behind most of the arguments at the table. Here are the rules as the National Mah Jongg League (NMJL) sets them out, in plain words.

How many jokers are there?

An American set has 8 jokers among its 152 tiles. NMJL rules call for exactly eight. Some casual groups add extras or use blank tiles, but that's a house rule, not League play.

Where jokers can be used

A joker stands in for any tile in a group of three or more identical tiles: a pung (3), kong (4), quint (5) or sextet (6). A group can even be made entirely of jokers.

Where jokers can't be used

• Never as a single tile or in a pair. This is the rule that rules out jokers in "singles and pairs" hands, and in hands built from single tiles like NEWS or the year.
• Never passed in the Charleston. A joker you're dealt stays in your rack. See the Charleston, explained.

Discarded jokers are dead

A joker that's been discarded can never be picked up. Nobody can call it, for an exposure or for mah jongg. It stays in the discards for the rest of the hand. That's why you'll rarely see a strong player throw one away.

The joker exchange

If a player has an exposure on the table containing a joker, you can take that joker by giving them the real tile it stands for. This is the joker exchange (sometimes called a joker swap).

1. Only on your turn. Draw from the wall (or call a discard) as normal.
2. You must hold the real tile. Put it in place of the joker in the exposure.
3. Take the joker into your hand. The player whose exposure it was can't refuse.
4. Then discard to end your turn.

A few details people often get wrong:

• Any player can exchange, including the player who made the exposure.
• Only exposed jokers can be exchanged. Jokers in someone's concealed rack are off limits.
• You can't add a redeemed joker to an exposure you've already made. Since 2019 the League has said that once an exposure is made, you can't start a joker exchange and then put that joker into the exposure.

When rules differ

The League publishes its rules and a new card every year, and some details move between editions. When your group disagrees, the current NMJL card and rulebook settle it.

Jokers in other styles

American mahjong isn't the only game with jokers. Indian Mahjong uses its 8 flower and season tiles as jokers, allows at most one joker per meld, treats discarded jokers as dead, and lets you steal a joker from an exposed meld by supplying the real tile. If you know the American exchange, you'll recognise it. You can play Indian Mahjong free on Mahjong Live while American mahjong is on the way.