For every hand, one player is designated as the oya 「親」, or dealer. At all instances, this player is also seated as east. During the game, player is denoted as the dealer with the dealer marker; or, the dealer marker notes the original dealer, while some other means to mark the dealer is used.
During the course of the game, the dealer position rotates among the four players. This can occur in two ways:
- A player other than the dealer wins a hand.
- The dealer fails to attain tenpai at ryuukyoku (exhaustive draw).
Seldom, a game can end without the dealer position ever changing. Notably, this scenario can occur if a player's points fall below zero beforehand. Of course, some rules allow continuance of the game, despite the scores.
The dealer seat has some benefits:
- If the dealer wins the hand, the wind seating does not rotate.
- If the dealer is tenpai at ryuukyoku (exhaustive draw), the wind seating does not rotate.
- The dealer's hand value is worth exactly or approximately 50% more than that of non-dealer hands.
- The dealer is always the first to grab four dealt tiles.
- The dealer always draws first and begins the hand.
Ideally, players greatly benefit by retaining the dealer position, an event known as renchan, in order to maximize point gains. Often, games may be won or lost regarding the dealer position.
Naturally, other players may force wind rotation by winning the hand themselves. Yet, at times, it may be beneficial for the dealer to simply concede the dealer position. Ideally, the dealer would prefer to let the wind seating rotate either when other players win points off of each other directly (by ron), other players win by tsumo using cheap hands, or being noten at ryuukyoku to minimize point losses.
Variation on the rotation rule may be applied depending on the requirement. Sometimes, the rule setting may require the dealer to win the hand, instead of merely achieving tenpai at ryuukyoku. This is to increase the pressure on the dealer to win hands. This also prevents the dealer from elongating the game by attaining additional hands by being tenpai at ryuukyoku.
The dealer is only disadvantaged when non-dealer players win by tsumo. In this case, the dealer pays approximately twice as much as the other players. This is significant during close games or on big hands, where the point differences may be adequate enough for a place change.