American Mahjong Rules for Beginners

This is the rule layer people talk through at the table

Once the tile structure is clear, the next layer is table rules. This is where players talk about concealed lines, exposed jokers, dead hands, and house customs. Knowing these boundaries makes you much calmer when something unexpected happens mid-hand.

Concealed lines, exposures, and joker exchange

If a line on the card is marked C, it must stay concealed until Mah Jongg. Exposed sets are public and stay public. When a joker sits in an exposed set, another player may exchange the natural tile that belongs there for that joker, following the usual exchange rules at the table.

• C means concealed, not mostly concealed.
• Exposed sets are public information.
• Exposed jokers can be exchanged with the natural tile that belongs in that set.

Dead hands, Mah Jongg calls, and house rules

A dead hand is one that can no longer finish legally as played. That can happen because of an illegal exposure, a false Mah Jongg call, or another rule break that your table treats as fatal. The card sets the hand value, but payment customs and a few edge rules can vary by house, so it is always healthy to ask before the game begins.

• The card line sets the hand value.
• Ask about house rules before the game starts.
• Mah Jongg can complete shapes that ordinary exposure claims cannot.