Definition
The joker exchange lets a player, on their own turn, swap the natural tile a joker represents for that joker in any exposed set on the table.
Do it in the right order. Pick from the wall and rack, or call and expose, and only then exchange. Under League rules, exchanging before you have picked makes your hand dead. The joker then goes into your hand, and only exposed jokers can be taken, since hidden ones are safe. Once you have handed your natural tile to the other player, set it on their rack, or taken hold of their joker, the exchange is committed, and you cannot take your tile back or put the joker back.
At the table
The exchange is the reason exposing early costs you. Any joker sitting in your exposure can be taken by anyone holding the natural it stands for, on their turn, and you cannot refuse. One mistake is the order. Under League rules you pick and rack, or call and expose, before you exchange, and doing it the other way round makes the hand dead. Another is reaching before you have decided, since a committed exchange cannot be taken back. Check first that your tile matches the set exactly and that you want the joker.
Also called redeeming a joker.
Read the full guide: The Joker Exchange in American Mahjong: How Redeeming a Joker Works.
Lesson 6, Jokers: Power & Discipline, teaches this in its step "The joker exchange". It comes with the Club. See what Lesson 6 covers.
See it on real tiles. The AI coach reads a dealt hand, free, and names the direction it goes for, what to keep and what to pass, at the free read.
Want the coach on call? The Club adds the coach for your own tiles and for each morning’s hand, all 10 lessons, and every new NMJL card taught the week it lands, for $14.99 a month, cancel anytime. See what the Club includes.
Related: Jokerless, Joker, Calling, Courtesy pass. All 52 terms.