Mahjong Calls and Exposures
A call claims the most recent discard and places it into a completed face-up group. Calls are useful because they can finish a needed pung or kong, but every exposure also reveals information and locks part of the hand into one interpretation.
What a legal exposure requires
- One current discard
- Only the most recently discarded tile may be claimed.
- One complete group
- The discard must immediately complete a pung, kong, quint, sextet, or the entire winning hand.
- Identical tile identity
- All natural tiles in the group must be exact matches.
- Compatible card line
- The group must fit a real line the player can legally complete.
- Permitted exposure status
- A concealed hand cannot contain an ordinary exposure.
Legal and illegal reasons to call
Legal
The discard completes a three-or-more identical-tile group shown on the card, or completes mahjong.
Illegal
The discard merely improves the hand, completes only a pair during ordinary play, or is wanted for a possible future combination.
How to make the exposure
- Call the tile before the next player completes a draw.
- State the group, such as “three bam” or “north kong.”
- Take the discard and place the complete group on top of the rack.
- Arrange all tiles so the group is unambiguous.
- Discard one tile to complete the turn.
An exposure is public information
Every exposed group tells opponents something about the possible card line, suit structure, and remaining needs. Strong play weighs the speed gained by calling against the information revealed.
Calling questions
Can a discard be called to exchange for a joker?
No. A natural tile used for a joker exchange must come from the player’s hand during the player’s own turn.
Can two players call the same discard?
Priority rules apply. A valid mahjong call outranks an exposure call; otherwise the nearest eligible player in turn order generally has priority.
Can a player expose a pair?
Not during ordinary play. A pair may be completed with a discard only when that discard gives the player mahjong.