When can you call a tile in American Mahjong?

Three choices, not one

When another player discards, decide what taking that tile would legally complete. Wanting the tile is not enough.

• Let it goLeave the discard. You cannot collect it and save it for a possible group later.
• Call for an exposureUse the latest natural discard to complete an allowed group of three or more identical tiles, then expose that group.
• Call for Mah JonggUse the final natural tile to complete a valid hand on your current card. This is a winning declaration, not an ordinary exposure call.

Only the most recent discard is available, while its call window is still open. You cannot return to an older tile in the discard area. A discarded Joker can never be claimed.

Calling for an exposure

For an X hand, check both the required group and the tiles you already hold. The called discard must finish the complete exposure immediately. Matching Jokers may help only within an eligible group of three or more identical tiles.

If you hold only one 6 Craks and no usable Joker, that same discard does not complete the required pung. You cannot take it merely to keep a pair in your rack.

C means concealed: do not make an ordinary exposure for a C hand. The final natural tile for a valid Mah Jongg is the exception below.

Can you call for a pair? Only for the win.

You cannot claim a discard simply to expose a single or pair. You may call the final natural tile if it completes a valid Mah Jongg hand, including a required single or pair. This can also apply to a C hand.

Before declaring, check the complete line: tiles, suits, notes and whether the hand is X or C. A partial illustration or a correct practice answer is not proof that a real hand wins.

What happens after a call

1. For an exposure, take the called tile. Put it with the matching tiles from your rack and display the entire required group face up.
2. Discard one concealed tile. Unless the move completes a valid Mah Jongg, finish your turn by discarding. Count your exposed and concealed tiles together.
3. Play continues from you. A legal exposure call can skip players between the discarder and the caller.

A Mah Jongg call instead leads to revealing and checking the completed hand. Do not discard after a valid winning declaration. Calling priority and disputed or misnamed tiles need the full rules; they are outside this short guide.