Ba
A ba 「場」, or wind round, is a length of gameplay where each player gets 1 chance to be the dealer (barring a premature game end). Each wind round is associated with a single cardinal direction and its corresponding wind tile. Each wind round lasts a minimum of 4 hands, but can be extended when a renchan occurs. For the remainder of this article, the term round will refer to a wind round, although it is sometimes used to mean kyoku instead.
Usually, a match is played for a set number of rounds.
- A hanchan 「半荘」 lasts for 2 rounds - east and south. In modern Japanese play, this is the normal game length.
- A tonpuusen 「東風戦」 lasts for 1 round - east.
- An iichan 「一荘」 lasts for 4 rounds - east, south, west, north. It's rare for a game of Japanese mahjong to be played this long, but is considered the "traditional" game length.
Some rules sets allow the match to extend into additional wind rounds if no player has met the goal score.
The first round in a match is always associated with east, and subsequent rounds follow in the standard player order of south, west, and then north. In a ruleset which allows the game to continue beyond four rounds, the rounds would repeat so that the fifth round would be east, the sixth south, and so on.
The major difference in gameplay between each round is the round wind tile: the wind tile that matches the current round is more valuable, as it can be used by any player to score the yakuhai yaku. Also, if the match is extended past its predetermined round length, the game usually enters a "sudden death" mode, where the round ends as soon as the goal score is met.
Dealer rotation
A complete round gives each player the opportunity to be the dealer once. After each hand, the dealer may be permitted to repeat the hand with an additional honba counter. While this is subject to many variations, the most common rule is that a repeat occurs if the dealer wins the hand, is tenpai when an exhaustive draw occurs, or when an abortive draw occurs. A chombo also causes the hand to be replayed, but without a honba counter. Some variations provide that if the dealer commits a chombo, the deal does rotate.
When the deal rotates to the fourth time, back to the player who was originally the dealer, the round ends and either the game is over or a new round begins.
Round/Hand organization
Each hand is organized by the round wind, then a number indicating which player is the dealer. For example, East 1 is the first dealer's turn in the first round. East 2 is the second dealer's turn in the first round.
Each time the dealer repeats, the round gains an extra honba. So East 1, Honba 1 would be the second hand of the first dealer in the first round.
Additional rounds
In many rulesets, a goal score must be reached by at least one player for the game to end. If this score is not met by any player at the end of the normal rounds of the game, the game proceeds into an additional round, or enchousen 「延長戦」. This round is usually played as sudden death: the game end as soon as a player reaches the goal score. Usually, but not always, the game will also end at the end of the additional round regardless of score; and the game will not proceed into a second additional round.