Suppose you are dealt the following hand:
Your partner opens 1, and you respond 1. Your partner then rebids 2. What should you bid now? Rebidding your spades would promise a 6-card suit, and bidding notrump would promise a heart stopper. Furthermore, you probably want to be in game, so it seems that you must choose between 4 and 3NT!
Fourth-suit forcing is a convention designed to deal with this conundrum. Here's how it works:
For example, in the situation above you would simply bid 2. Partner should bid 2 with three-card spade support or 2NT with a heart stopper.
When is a suit bid forcing? A new-suit bid by responder is always forcing unless it is an escape from notrump. The "fourth-suit forcing" convention states that, in addition, a bid of the fourth suit by responder may be artificial. In particular:
EXCEPTION: There is some disagreement about whether 1 may be artificial in the sequence:
|1 1 1 1|
Make sure to discuss this situation with your partner.
How much strength is required? Quite a bit:
NOTE: The 1 bid in the sequence:
|1 1 1 1|
does not promise any extra strength if it is natural.
When to Use Fourth-Suit Forcing. There are two main situations where you might want to use fourth-suit forcing:
Bid 2. Partner should respond 2 with 3-card spade support.
Bid 2. Partner should respond 2NT (or 3NT) with a spade stopper.
Opener's Third Bid After the fourth-suit bid, opener has the following priorities:
In addition, opener may jump on his third bid to show extra strength.
Other Uses of Fourth-Suit Forcing Some partnerships like to use fourth-suit forcing to distinguish invitational hands from game-forcing hands. For example, consider the following two auctions:
Responder shows a 6-card spade suit in both, but in different ways: responder jumps directly to 3 in the first auction, but meanders his way there in the second.
Most partnerships like to play that the first auction shows an invitational hand with spades, while the second auction shows a game-forcing hand with spades (or vice-versa). Many partnerships that use this treatment also use a variant of fourth-suit forcing called fourth-suit game-forcing, where a bid of the fourth suit is always forcing to game. If you like this treatment, be sure to discuss it with your partner.
Competition Fourth-suit forcing is off during competition. However, it is common to use a cuebid of the enemy suit as an artificial forcing bid during such an auction.