Agari houki
Dead hand (アガリ放棄 agari hōki) is a lesser penalty compared to chombo, resulting in the player to be unable to win the corresponding turn when the minor rule violation was committed.
Consequences
When the player's hand is declared dead, he is unable to make any more calls during the hand: He may not make tile calls, win by ron or tsumo, or declare riichi.
The player must continue, however, to draw and discard the tiles as he usually would in order not to deal into other players' hands. If the player called riichi before his hand was declared dead, he loses the 1000 points deposited and has to continue as usual when being in riichi, discarding the tiles after drawing them.
A dead hand is never considered tenpai, because a win may not be called.
Making any type of call with a dead hand results in a chombo.
Causes
These scenarios usually result in a dead hand.
Wrong amount of tiles
At any point of the game, if the player has less or more than 13 tiles before drawing the next tile, the hand is considered dead.
Drawing from the dead wall
Accidentally drawing from the dead wall will result in a dead hand.