Do Not Put Tiles Down Until the Tile Is Yours
Exposing for a claim you do not win is a violation in its own right, and it kills the hand. No beginner guide we checked warns about it.
Calling a discard feels great, especially early on. You spotted it, you spoke up, and you get to put something down where everyone can see it. That eagerness has a specific cost, and it is steeper than it looks.
The rule
If you lay tiles on your rack for a discard that does not end up coming to you, that is not a harmless false start. It kills your hand.
The order matters. Call, wait until the tile is actually coming to you, then expose. Not the other way round.
When it bites
Two people can want the same discard, and the ladder that decides it does not care who spoke first.
Work down it: a mah-jongg claim beats a claim for an exposure, even when the other player already has tiles down. Within the same kind of claim, the player next in turn after the discarder wins — unless the other caller had already begun exposing for that specific tile.
So here is the situation that catches people. You call for an exposure and start laying tiles down. Somebody else calls the same tile for mah-jongg. They take it. You are now holding an exposure for a tile you never received.
Worse still, if their mah-jongg turns out to be invalid, the tile stays with them and their hand is dead — and so is yours, because you exposed without successfully claiming.
The other version of the same mistake
You call, then look at your card again, then change your mind.
If tiles were already down, the same rule applies. If they were not, you have still handed three opponents a free piece of information about your hand and received nothing for it. They may hold that tile back for the rest of the game, or throw it immediately on the assumption you can no longer take it.
Check the line on your card before you speak. Not while your hand is moving toward the rack — before the word leaves your mouth.
Why nobody tells you this
We checked eight teaching sources while building this site. Every one of them explains how to call a discard. Not one of them warns that exposing before the claim succeeds is itself a violation.
It is an easy thing to leave out, because the rule only appears in the errors-and-penalties material rather than in the how-to-play walkthrough. It is also exactly the mistake an enthusiastic beginner makes in their first few games.
When you have read it all: the rules workbook, 105 questions with an answer key that cites the rule behind every answer, $19.
Where this comes from
The violation and its consequence are stated in the American Mah-Jongg Association's rulebook, in its treatment of conflicting claims. The priority ladder itself is confirmed independently by the AMJA, Tom Sloper's rules FAQ quoting the League, and I Love Mahj.
Where both players have already begun exposing, no official rule exists. The common recommendation is to fall back to turn order — agree that at your table before you need it.