Jokers in American mahjong: every rule in plain words

Where you can use a joker

Only in groups of three or more matching tiles.

If your hand needs three 7 craks and you have two, a joker can be the third. If your hand needs a kong of 4 dots and you have one, three jokers can fill it. Jokers work the same way in groups of flowers, winds or dragons.

Can you use a joker in a pair?

No. Never in a pair and never as a single tile.

This catches out many new players, especially with hands that use single tiles, such as one of each wind (NEWS) or a year like 2026. Every one of those tiles must be real.

Swapping for a joker

On your turn, if you hold the real tile a joker is standing in for in any exposed group, you may trade it for the joker.

1. Wait for your turn. You may swap after picking from the wall or after calling a discard, before you discard.
2. Find the joker. Look at every exposure on the table, including your own. A joker in a group of 5 bams can be swapped for a real 5 bam.
3. Make the trade. Place your real tile in the group and take the joker into your hand.
4. Finish your turn. Discard as usual. You may make several swaps in one turn if you have the tiles.

Swapping is one of the best moves in the game. It also explains why experienced players hold on to tiles that match other people's exposures.

What happens to a discarded joker?

Nobody can call a discarded joker. It stays in the discards.

Throwing away a joker is usually a mistake. It may make sense late in a game as a safe discard when every other tile might help an opponent win, but most players hold jokers to the end.

Jokerless hands

A hand made with no jokers at all is called jokerless. Under League scoring a jokerless win pays double, as long as you announce "jokerless" when you declare. Some hands, often those with lots of singles and pairs, are jokerless by nature because jokers cannot be used in them.