A reverse, in the card game contract bridge, is a bidding sequence designed to show additional strength without the need to make a jump bid; specifically two suits are bid in the reverse order to that expected by the basic bidding system. Precise methods and definitions vary with country, bidding system and partnership agreements.
In Standard American a reverse is defined by William S. Root as "... a nonjump bid at the two-level in a new suit that ranks higher than the suit you bid first", and by Bridge World. as "a non-jump bid in a new suit that bypasses a bid in a lower-ranking suit already bid by the same player".
The Acol definition is somewhat wider and includes any bid of a new suit by opener higher than two of their first suit.
An example satisfying both definitions is:
The last bid is a reverse.
Note responder avoided making an initial response of 1♥. Despite this, opener chose to bid 2♥, apparently seeking a fit that is unlikely to exist. This seemingly odd bidding is the "reverse" of what one would expect with a minimum hand (keeping the bidding low) and is used only with strong hands as it consumes bidding space.
A relatively easy way to identify the reverse uses the "gap" principle. A simple reverse is made when:
1. Opener opens one of any suit (except spades).
2. Responder bids at the one level.
3. Responder's bid leaves a "gap" between the two bids.
4. Opener then bids "into the gap" at the two level.
For example, in the example above, the response created a "gap" of the red suits. When opener bids a red suit that was "in the gap" then that constitutes a reverse.
Opener's reverse may face a weak responding hand with which responder may have intended (over a simple suit rebid) to rebid his own suit or taken a preference to opener's first suit at the two level. Opener's reverse still allows responder to rebid his suit at the two level, but a preference to opener's first suit must be at the three level. Thus, opener's reverse must show values at least one trick beyond the minimum needed to open.
For example, following 1♦ - 1♠ ; 2♥ - ?, responder may have a weak hand such as ♠QJ86 ♥K2 ♦8762 ♣Q74 and be planning to rebid 2♦, a simple preference, if opener made a typical rebid such as 1NT or 2♣, and to pass if opener rebid 2♠ or 2♦. However, following the reverse, he must now rebid 3♦. Thus the reverse has forced the partnership to commit to taking nine tricks instead of eight - based on the extra strength of opener.
Examples of reverse bidding sequences:
A special case exists when responder makes a two-over-one initial bid. Since a two-over-one response shows more than a minimum, generally ten or more, opener does not need as strong a hand to reverse the bidding at that juncture. The modern trend is therefore to allow such a reverse bid after a two-over-one initial response with a minimum opening hand.
Opener's reverse need not be in a four-card or longer suit; it can be made on a powerful three-card minor suit, such as ♦AQJ. This approach is useful in investigating notrump contracts and when no other four-card suit is available to bid.
Reverse bids are generally considered to be forcing, with subtle variations depending on system:
These examples illustrate high and low level reverses:
In some variants of 2/1 game forcing, the major-suit reverse after the sequence 1♦ - 2♣ doesn't promise extra values - opener may merely show a 4-card suit or a stopper. Kaplan-Sheinwold treats 1♦ - 1M; 2♣ as a reverse although this is not standard in other systems.
Most partnerships play a rebid of responder's suit or of 2NT in response to opener's reverse as weak and other responses as forcing to game, including preference for the opening suit. Thus, after
responder's rebids are:
Most standard methods treat a responder's reverse as a game force. Responder's reverse usually follows a same suit rebid or a notrump rebid by opener, because otherwise it would be treated as conventional. Typical responder's reverse sequences are:
The term "jump reverse" denotes a jump bid in a suit in which a non-jump bid would be a reverse. Jump reverses after a major-suit response carry a special meaning. Most expert partnerships utilise this bid to denote game-going values with shortness (often specifically a singleton) in the suit bid and support for partner's major suit. An example of a jump reverse is:
1♣ - 1♠; 3♥
Partnerships utilising this agreement commonly agree that in this situation a splinter bid (i.e. a double jump in a new suit) indicates a void. This is also the understanding used in Bridge World Standard, though other options may also be used.
Jump reverses after a minor-suit response commonly show splinter raises, too.
1♦ - 2♣; 3♥
Jump reverses after a 1NT response to a minor opening are often used to indicate game-going values with shortness in the suit bid (a singleton or void) and six cards or more in the minor suit opened. This agreement facilitates partner in deciding the final contract (in most cases 3NT or a game or slam in the opened minor).