Renchan 「連荘」 functions as the dealer repeat. When renchan occurs, the wind seating does not rotate. Consequently, the winds do not rotate. The hand is played again with the same dealer. Additionally, a honba is added, slightly increasing the value of the next hand. This rule is invoked when either the dealer wins the hand or the dealer retains tenpai when no one wins the hand.
Renchan factor significantly into game strategy: because the dealer scores more points for winning, it is generally preferred to have as many hands as dealer as possible. While the exact conditions for renchan vary by ruleset, in general, a renchan is a bonus given to a dealer who does well.
Renchan are not the only situations where a honba can be added, nor the only situations where the hand can be repeated with the same dealer. Honba are also added if the deal rotates without a player winning, and the hand can be repeated with the same dealer in event of a chombo. If a chombo occurs, however, no honba are added.
Under all rulesets, renchan occurs any time the dealer wins a hand. Under rulesets which allow abortive draws, renchan occurs every time an abortive draw occurs.
Beyond these commonalities, the conditions for renchan can vary from ruleset to ruleset. In some rulesets, they can vary depending on the wind round of the game. If this is the case, then renchan is usually more difficult in the east round, and more commmon during the south round.
The most restrictive form of renchan rules is agari renchan (win renchan), under which there are no other conditions for renchan. In particular, renchan never occurs at an exhaustive draw.
The most common form of renchan is tenpai renchan, under which a renchan also occurs at an exhaustive draw if the dealer declares a tenpai hand.
The most permissive form of renchan is ryuukyoku renchan, under which a renchan also occurs at any exhaustive draw, regardless of players' tenpai status. Usually, this variation is only found in the south round where the east round is played with tenpai renchan.
If multiple ron is permitted, there may be a variation to the rule that the dealer always get a renchan after winning the hand. Under some rulesets, if a multiple ron occurs and the dealer is one of the winners, a renchan occurs in a multiple ron only if the dealer is the first player in turn order after the player who dealt in, similar to how atamahane awards the win only to the first player in turn order.
If nagashi mangan is used, then its interaction with renchan depends on how it is scored. Under some rulesets, nagashi mangan is scored as a winning hand, in which case renchan occurs if the dealer was the player to complete it. Under other rulesets, nagashi mangan is treated as a replacement for the usual points exchange at an exhaustive draw, in which case the renchan occurs based on the usual rules for an exhaustive draw. This may allow the dealer to complete and score nagashi mangan but, because they are not tenpai, to lose the deal.
In general, the dealer wants to win repeatedly and quickly in order to trigger renchan. The dealer receives a score bonus for winning, and while taking slower, bigger hands may be enticing, it is better to save that for large hands (mangan or better) in order to minimize the risk of someone else winning and the deal rotating.
Every time the dealer wins a hand, they receive a renchan. This means that they will receive the points for winning the hand, and then the hand will repeat with the same dealer. The points exchange means that the game is no closer to its conclusion, but the dealer now has more points, putting them into a better situation. If the dealer wins repeatedly, these points can add up, and the points for the honba will also add up.
If tenpai renchan is the rule in effect, then as a hand nears an exhaustive draw, the dealer is encouraged to remain tenpai in order to claim a renchan. This may result in riskier play than usual, since the dealer has more at stake than the other players.
Near the end of the game, the strategy regarding renchan can change. A player who is very far behind is hard-pressed to win many renchan in order to climb back up and possibly surpass other players' scores, while a player in first wants the game to end as quickly as possible. Nearing the end, a dealer with a sizeable lead may deliberately avoid a renchan (especially if agariyame is not being used) in order to avoid the risk of a large tsumo, and to hasten the end of the game.