What a joker can do
In American Mah Jongg a joker is a wild tile with limits. It can stand in for any tile in a group of three or more identical tiles — a pung (three), kong (four), quint (five) or sextet (six). Two real red dragons and a joker make a perfectly good pung of red dragons.
The limits matter just as much. A joker can never be used as a single tile or as part of a pair, and it cannot be used in a run of consecutive numbers because American hands describe runs as single tiles. That rule shapes strategy: hands with many pungs and kongs are friendlier to jokers than hands made of singles and pairs.
Joker exchanges
If a player has exposed a group containing a joker, any player may, on their own turn, take that joker by giving the real tile it represents. If an opponent has exposed three green dragons made with a joker and you hold a green dragon, you can swap it in and take the joker for your own hand.
Exchanges can be made after drawing or after claiming a discard for an exposure, and several can be made in one turn. Because jokers are so valuable, watching for exchange chances is a key American skill — and exposing jokers is a risk, because they may be taken away.
Jokers and discards
A joker can be discarded, but it is rarely wise. When a joker is thrown, nobody may claim it for an exposure, and the player who discarded it usually describes it by naming the tile discarded just before it. Most players only throw a joker defensively, when it cannot help their hand and keeping it would mean breaking a hand that could still win.
Jokers also may not be passed during the Charleston. They stay in your hand from the deal onward, which makes a hand with several jokers worth protecting.
Jokerless hands
Winning without any jokers earns a bonus under the standard rules: payments are doubled. Some card hands also forbid jokers outright — typically hands made of singles and pairs. Players with a strong natural hand sometimes deliberately avoid using jokers to collect the jokerless bonus.
For beginners, the main message is simple. Jokers make American hands much easier to complete, but only in groups of three or more. Before committing to a card hand, count how many of its tiles could ever be replaced by a joker.
