Three players asked variations of the same question last week, so here is the answer, with the parts that surprise people spelled out.
The rule in one line
If you take a discarded tile to complete a group, that group goes face-up on the table and stays there. If the hand you are playing is marked concealed, you cannot do that at all. And calling is never compulsory.
What you must expose
| Action | Must it be exposed? | What it costs |
|---|---|---|
| Claiming a discard to complete a pung | Yes, face-up | The group is locked, and the concealed bonus is gone |
| Claiming a discard to complete a kong | Yes, face-up | The same, and the fourth tile came off someone else's discard pile |
| Claiming a discard to complete a quint | Yes, face-up | The same. Only the card's quint lines ask for one |
| Completing a group from your own draw | No | Your hand stays as it was |
A pung is three of a kind, a kong is four, a quint is five. The shapes are what goes on the table:
What must never be exposed
Nothing, if the line you are playing is marked concealed. That is what concealed means. The bonus those lines carry is paid for by never putting a group on the table, so exposing one does not shave a few points off the score. It takes you off that line altogether.
Read the line before you call, not after. Once the tiles are face-up, they are the evidence, and there is no version of this where the group goes back into your rack.
What an exposure costs you
Three things, roughly in the order they matter:
- The concealed bonus, for the rest of the hand. Not for the turn, not until things settle down. The hand is no longer concealed.
- The information. An exposed group tells the other three players what you are collecting. They cannot take your tiles, but they can stop feeding you.
- A joker, if you used one. A joker in an exposed group stays with that group. You cannot pull it back out when the real tile finally arrives.
That third one catches somebody every season. The rule is not that the joker is wasted. Once it is exposed you cannot take it back yourself. What can still happen is the second question below: another player who holds the tile it stands for can claim it.
Why passing is a play, not a mistake
Beginners apologize for passing. They see a tile that would complete a group, they let it go, and they say sorry as if they had missed a turn.
If you are on a concealed line, passing is not a missed opportunity. It is the only way the hand works. There is no partial version of concealed: one exposed group and the whole route is closed. Knowing which lines you are willing to expose for, before the hand starts, is most of the decision.
Three questions that come up every week
"I called the tile and then saw it broke my hand. Can I put it back?" No. An exposure is final.
"Someone else exposed a joker. Can I claim it?" Yes, if you hold the tile that joker represents. The jokers page sets out the conditions, and jokers are wild but never for a pair covers what a joker can and cannot stand in for.
"If I expose one group, can I still win?" Yes. You can complete the hand and call it. What you cannot do is collect the concealed bonus, because the hand is not concealed any more. The concealed hands page sets out what those lines require.
When in doubt
Ask the table before you touch the tiles. Nobody has ever been criticized for asking first.