4th Suit Forcing

Fourth Suit Forcing ("FSF") is artificial, is forcing to game, and is alertable although some play that is just forcing for one round, in which case it is not alertable.

The fourth suit bid must be bid on at least the 2 level, it could be short, and is assumed to be unstopped until indicated otherwise, although he normally has at least a half-stop (e.g.: Qxx). If opener has the suit stopped, he will usually bid NT, although this page on the ACBL web site says that opener's first obligation is to raise partner's suit with 3-card support.

It also says that opener can rebid his 2nd suit to show 6+ of his first (minor) suit and 5+ of his 2nd suit (usually a major). If opener's hand does fit one of these other bids, he should rebid his first suit.

If the 4th suit bid is 1, it is natural and forcing, but not game forcing. A jump to 2 is FSF but denies 4 spades.

Only responder can make a FSF bid and the bidding goes something like 1 - 1 - 1 - 2.

FSF is off when..,

• responder is a passed hand
• the opponents overcall or (optional) double
• the 4th suit is bid on the 1 level
• opener rebids 1NT, in which case New Minor Forcing can be used.
• opener reverses on his 2nd bid
• responder makes a 2/1 bid on his 1st turn.

FSF denies all of the following:

• a 6-card suit with at most 1 loser
• a stopper in the 4th suit (bid 2N).
  [But n Bul 2020-10 p.60, we are told to bid FSF with AQ763-6-Q92-KJ83 after 1H-1S, 2C.]
• 3-card support for partner's opening major
• 4+card support for partner's 2nd suit. [But note the hand above with 4 of pard's clubs.]

For a fuller treatment, click here.