Five-card majors is a contract bridge bidding treatment which is very powerful and standard in most modern bidding systems, including Standard American, Bridge Base Basic, and 2-over-1 game forcing. Partnerships who agree to play 5-card majors will usually only open the bidding in a major suit with at least five cards in that suit and with at least 13 points.
Typically when a bridge player makes a natural bid in a major suit (hearts or spades), he is promising at least four cards in that suit and asking partner if it will be an advantageous trump suit for the partnership. Because of the power of naming a trump suit with an 8-card fit, the responder with four or more cards of that suit will support his partners bid as if to say "we have found our 8-card fit."
With 13 cards in each suit, an 8-card fit implies that only five trump cards can be held by the opponents. They will most likely be distributed 3-2 or 2-3 among the opponents, so playing trump for three rounds will probably draw all trump cards from the opponents and leave two additional trump to be used separately for offensive purposes. However if the trump cards break 4-1 or 1-4, then drawing trump will result in no trumps left for offensive purposes.
The value of 5-card majors can be understood then on two levels:
- When partnerships have a 5-3 distribution in a major suit, the 8-card fit is easier for the player with the three cards to find. The strong preference to play duplicate bridge in the major suits at the game level makes the 5-card major convention very attractive.
- When the trump suit can be declared with a 5-3 fit, then often one extra trick can be taken due to the extra trump card in declarer's hand because
- if the opponent's five trump cards are distributed 3-2 or 2-3, then declarer will have two remaining trump cards to use in continuing play.
- if the opponent's five trump cards are distributed 4-1 or 1-4, then declarer can pull trump for four rounds and still have one trump card in declarer's hand for continuing play.
But 5-card majors have several drawbacks :
- Immediate 5-3 fits occur less frequently than immediate 4-4 fits (16.3% of the time versus 11.8%) reducing the probability of auctions such as 1♥-3♥
- Since playing 5-3 fits needs (at least) three turns to establish so there is often no trick gained by ruff in the short hand, while 4-4 fits can lend themselves to cross-ruff. In the 5-3 case, the two remaining established cards (assuming the opponents cards are 3-2 or 2-3) can also bring tricks in no trumps, if there is an entry to the hand which owns these cards.
- Immediate discovering of 5-4 fits is possible on one way with 5-card majors, and on two ways with 4-card majors.
- Hands with 4-card majors and no 5-card major are opened by one of a minor suit, which is less informative and more easily preempted by opponents than a 4-card major opening.
To play 5-card majors
Both partners must agree to follow the 5-card major bidding treatment on their opening bid. Opener must have at least five cards in hearts or spades to start the bidding with that suit. Responder is expected to show support with 3-card support, indicating an 8-card fit. With only four cards in a major suit, the opening bidder is expected to open one of a minor suit (which may show less than 4 cards in that suit) or 1NT if in the agreed points range. After the opening bid, the 5-card limitation is no longer in effect and any other bid typically promises only four cards as before.
- at least 13 points and interest in winning the contract,
- no 5-card major (else opener would have bid it, unless also holding a 6-card or longer minor),
- no 4-card diamond suit (else opener would have bid 1♦).
In this case, a 1♦ bid may also be on 3 cards, to cope with a 4-4-3-2 shape. This method is used in Standard American bidding. The alternative is for 1♦ to promise at least 4 cards, in which case the 1♣ opening may have to be made on a two card suit.
There is strong pressure upon responder to bid a 4-card major even after an intervening bid, or to show it indirectly by a negative double. In some methods, 1♣-(1NT)-2♥ as first response may promise only four hearts. Opening bidder will not raise the 2♥ bid with only three hearts.
Most bidding systems use five card majors in conjunction with a strong no-trump. However, it is also possible to play it with a weak no-trump, as practiced by some club and tournament players in the United Kingdom.
- Learn to Play Bridge Software ACBL
- Zar Points Bidding Backbone at www.archive.org (see page 31).
- Editors: Francis, Henry G.; Truscott, Alan F.; Truscott, Dorothy A. (2001). The Official Encyclopedia of Bridge, 6th edition, page 419. Published by American Contract Bridge League. ISBN 0-943855-44-6.