Fourth-Suit Forcing

        Suppose you are dealt the following hand:

  AQ832
  54
  A3
  K95

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:

If responder bids the fourth suit on his second bid, it says nothing about the suit in question, and simply asks opener to bid again.

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:

A new-suit bid by responder may be artificial if:
        •    It is responder's second bid, and
        •    It is the fourth new suit bid in the auction.

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:

A fourth-suit bid at the 2-level promises at least invitational strength.
A fourth-suit bid at the 3-level shows game-forcing strength.

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:

Use fourth-suit forcing when:
        1.    You have a 5-card major and want to check for 3-card support, or
        2.    You are interested in notrump game but don't have a stopper in the fourth suit.

EXAMPLE:

  KJ853         West    East (You)
  K83 1 1
  A64 2 ??
  82

Bid 2. Partner should respond 2 with 3-card spade support.

EXAMPLE:

  852         West    East (You)
  K2 1 2
  K76 2 ??
  AQ853

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:

1.    Show 3-card support for responder's major.
2.    Show a stopper in the fourth suit by bidding notrump.
3.    Rebid a 6-card suit (or a 5-card minor).
4.    Show 3-card support for responder's minor.
5.    Raise the fourth suit with good support (rare).

In addition, opener may jump on his third bid to show extra strength.

EXAMPLE:

1 — 1 — 2 — 2 — 2:     Shows 3-card spade support.
2NT:     Shows a diamond stopper.
2:     Shows 6 hearts (or 5 good ones).
3:     Shows 5 clubs.
3:     Shows 4-card diamond support.
3, 3NT,
  3, 4:   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:

West    East                West    East
1 1 1 1
2 3 2 2
2 3

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.