What X and C Mean, and Why It Changes Everything
One letter decides whether you can claim discards all game or only once, at the very end.
On this page
Every line on the card carries an X or a C. It is easy to skim past, and it governs more of how you play that hand than the tiles themselves do.
The two words
X is exposed. Exposures are permitted — you may claim discards to build groupings and show them on top of your rack as you go.
C is concealed. The hand stays hidden. You may claim a discard only as the tile that wins outright.
| X — exposed | C — concealed | |
|---|---|---|
| Claiming a discard | Yes, to build a grouping | Only to declare mahjong |
| Showing your tiles | Piecemeal, as you go | All at once, when you declare |
| Jokers | Allowed in any pung or larger | Also allowed in any pung or larger |
| Taking jokers off others | Yes | Yes |
The row that surprises people
A concealed hand is not a joker-free hand.
The C means hidden, not pure. Wherever a concealed hand contains a pung, kong, quint or sextet, a joker may sit in it exactly as it would in an exposed hand — the difference is nobody sees it until you declare.
Playing concealed does not stop you taking a joker off somebody else's exposure. You give the natural tile, you take the joker, and it goes straight into your hidden hand.
The two beliefs that go together — "concealed means no jokers" and "concealed means no exchanges" — are both wrong, and they are wrong for the same reason: C constrains what other people can see, not what your hand may contain.
Where concealed hands actually die
The mistake is not usually about jokers. It is claiming a discard to build — broken concealment, which is one of the five ways a hand goes dead.
It is an easy error, because the line looked like a perfectly ordinary pung and somebody threw exactly what you needed. The letter is the only thing standing between you and taking it.
Why anyone plays concealed at all
Two reasons, and they pull in the same direction.
Nobody knows what you are building. An exposed hand leaks with every grouping you put down; opponents adjust their discards accordingly. A concealed hand tells them nothing until it is over.
They are worth more. The values sit on the card and change every year, so you will read them off your own — but concealed lines are priced above comparable exposed ones, because you have given up the ability to claim your way there.
The cost is real, though. You are drawing everything yourself, and if the tiles do not come, you have no way to accelerate. Beginners are usually right to leave them alone for a while.
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 definitions — concealed meaning all concealed with a win by discard permitted, exposed meaning exposures permitted — follow Tom Sloper's rules FAQ, which cites both the League's own rulebook and The Red Dragon & The West Wind by page. That a concealed hand may contain jokers and may still take them from others is confirmed there and by I Love Mahj.
No hand values appear here. They are card-specific and change every year.