Rules, Penalties, and Dead Hands:

Dead hands: A player should not announce that their hand is “dead”. Even if a hand actually is dead, the player should continue to play defensively until someone else calls the hand “dead”. A player’s hand may go “dead” for a variety of reasons.

1. Too few or too many tiles
2. Invalid joker exchange: If a player proceeds to make a Joker exchange before the player picks and racks or calls and exposes, the player’s hand is “dead”.
   1. A Joker may never be passed during the Charleston. If it is, it must be given back.
   2. Once a symbol tile has been fully named or touches the table, it cannot be taken back to make an exchange for a Joker. Down is Down.
   3. A discarded Joker can NEVER be picked up. It is a “dead” tile.
3. Incorrect exposure: A player has exposed tiles which do not comprise a Pung, Kong, Quint, etc. NEWS, a year grouping or non-identical tiles.
4. No such hand: The exposed tiles do not represent any hand on the current Mah Jongg card.
5. Unwinnable hand: The exposed tiles indicate that a player is attempting to make a Mah Jongg which requires either single tiles or a part for completion. If three or more of the pair or four of the single needed tiles have already been discarded on the table or have been exposed by other players, the hand may be called “dead”.
6. Exposing tiles while playing a concealed hand: Player’s exposures indicate that a concealed hadn’t is being played and tiles have been exposed erroneously.
7. Picking ahead: if a player discards a tile before picking from the wall, the player’s hand is “dead”.
8. Picking out of turn: If a player picks out of turn the player’s hand is “dead”. If the tile is racked, it remains with the “dead” hand. If it is not racked, and another player immediately notices, it is placed back in the wall. If it is discarded, it is a dead tile and cannot be called except for Mah Jongg.
9. Picking from the wrong wall: If a player picks from the wrong wall and a tile from the wrong wall is racked, the player who picked the tile now has a “dead” hand.
10. Picking from the wrong end: if a player picks from the wrong end of the wall, the player’s hand is dead, and the other players continue playing from the proper end. The tile remains in the “dead” hand.
11. Pushing out the wrong wall: If a player pushes out the wrong wall, and a tile from the wrong wall is picked, the player who picked the tile now has a “dead” hand. The tile remains in the “dead” hand. The game continues from the wrong wall and then proceeds from the correct wall.
12. Mah Jongg in error: When a player declares Mah Jongg in error and exposes the hand, the hand is declared a “dead” hand. The disqualified player discontinues picking and discarding. The other players continue to play.
    1. No player should throw in or expose their own hand until the winner’s hand is verified.
    2. If a player calls Mah Jongg in error and the mistake is rectified immediately, before the hand is exposed or before other players expose or disturb their hands, the game continues without penalty.
    3. If a player declares Mah Jongg on a discard and places the discard on top of their rack or exposes tiles from their rack, and then finds they do not actually have Mah Jongg, they may change their declaration of Mah Jongg to a call for exposure. The game continues without penalty.
    4. If a player calls Mah Jongg in error and exposes part or all of the hand and all other hands are intact, the game continues but the declarer’s hand is “dead”. All tiles are returned to the rack. A Mah Jongg hand “intact” means that a player has not exposed tiles from their hand, other than the tiles that had been called for an exposure before the player had declared Mah Jongg in error. “Dead” hand discontinues play, does not pick and discard.
    5. When a player declares Mah Jongg in error and has been playing an exposed hand, the Jokers which were in the correctly called exposure(s) BEFORE the error, may be redeemed by any of the other players with a like tile, when it is their turn. However, at the point the hand becomes “dead” the part of the hand that was in error is returned to the rack. When a player declares Mah Jongg in error and has been playing a concealed hand, no Jokers may be redeemed, and the entire hadn’t is returned to the sloped portion of the rack.
    6. If a player declares Mah Jongg in error and exposes part or all of their hand and all other hands are intact, the game continues, but the declarer’s hand is “dead”.
    7. If a tile is called and exposed resulting in Mah Jongg in error, the called tile must remain with the hand, even though another player wants to call the tile for an exposure. The tile becomes “dead” along with the rest of the hand. However, if another player wants the same tile for Mah Jongg, it may be called and used to complete the player’s hand for Mah Jongg.

These rules are from the Instruction Book "Mah Jongg Made Easy" Revised Edition 2024 from The National Mah Jongg League.