The forcing notrump is a bidding convention in the card game of bridge.
In standard bidding, the response of 1 notrump to an opening bid of 1 of a suit shows 6 to 9 high card points and is non-forcing. By agreeing that this bid is forcing (for one round), a partnership may use it for a greater variety of hands. The forcing notrump is used over major suits only; 1NT is always non-forcing over the minor suits.
A bid of 1 forcing notrump shows 6 to 12 HCP, denies the ability to make a single raise, and denies holding four spades if the opening bid was 1 heart.
Opener's rebid
Opener is forced to bid again as follows:
- 2 of original major shows a six-card suit
- 2 of a lower-ranking suit shows a second suit (which of necessity may be short—see below)
- 2NT is natural and invitational (showing about 18 HCP)
- 3 of a new suit (jump shift) is natural, normally agreed to be game-forcing, and shows about 19 points or more
When opener does not have a six-card original suit nor a four-card lower-ranking second suit, she will have to bid a short suit. Normally, she bids her three-card minor. If she has three cards in both minors, she bids 2 clubs.
If opener holds exactly four spades, five hearts, two diamonds and two clubs (and thus originally opened 1 heart), she bids 2 clubs (a two-card suit!). There is no point in showing the spades, because responder has denied holding four spades (having skipped the 1 spade response to bid 1 notrump). After a 1 spade opening, however, there is no distribution that would compel opener to rebid a two-card suit.
Responder's rebid
Responder categorizes her hand as either minimum (6-9 HCP) or invitational (10-12 HCP).
The minimum responder rebids are:
- 2 of opener's original major (shows two-card support)
- 2 of a new suit (shows a five-card or longer suit; some play a six-card or longer suit)
- pass denies either of the above
The invitational responder rebids are:
- 3 of opener's original major (shows exactly a three-card limit raise)
- 3 of a new suit (shows a six-card or longer suit)
- 2NT (natural)
- 3 of opener's second suit (shows at least four-card support)
Further bidding
When responder rebids 2 of a new suit, opener should pass with a minumum and two or more cards in the suit. With a singleton or void in responder's suit, opener should rebid her original major. Responder may yet have a doubleton there and pass, or will be able correct to 3 of opener's second suit or her own good six-card (or longer) suit. In this way, the partnership is normally assured of at least a seven-card fit.
Tactical raise
When responder has a very weak hand (0-4 points), but yet support for opener's major (three or more cards), standard bidding dictates a pass (because opener may have a very good hand and get overenthused after a single raise). This may allow the opponents to get into the bidding at a low level. Playing the forcing notrump, however, it is sometimes tactically advantageous to bid 1NT with this hand and then correct to 2 of opener's major. The 1NT bid tends to shut out the opponents and make partner cautious at the same time.
System implications
The forcing notrump is required for players using the 2/1 Game Forcing system, but may be used to advantage by other players as well.
