THE “C” ON THE CARD MEANS CONCEALED (Article 144)

Commentary: The NMJL card shows an X or a C in the right margin of each panel for each hand, indicating how the hand can be built.

• An “X” indicates that the hand can be built by claiming discards to make an exposure (i.e., meld, exposable; pung, kong, quint). When playing a hand that allows exposures, the player can call a discard at any time, even if it is not their turn.  
• A “C” indicates that a hand must remain concealed (i.e., closed) until the hand is ready to win with one tile. When playing a concealed hand, a player may make a joker exchange on their turn.

You can use Jokers in concealed hands, just as in exposed hands, as long as you use them in groups of three or more identical tiles (e.g., pung, kong).

When playing a concealed hand, you gather tiles by picking from the wall. You cannot claim a discard to make an exposure, but you can claim a discard to declare mah jongg if it completes your hand. You can also win by picking your final tile from the wall.

Joker exchanges are permitted while playing a concealed hand.

Question from a player:  Sometimes, I hear players refer to a hand with a “c” to the right of it as a closed hand. Is it okay to say closed, or do I have to say concealed? I noticed on the back of the card it shows, concealed.

Answer from the NMJL: The hands are clearly marked “C” for concealed, “X” for exposed and the value to be paid for each hand. An exposure is three of a kind (Pung), four of a kind (Kong), five of a kind (Quint) or six of a kind (Sextet).

Source: Mah Jongg Made Easy (2020 page 12); Choosing a Hand, back of National Mah Jongg League Card.