Jacoby 2NT: The Game-Forcing Major Raise

Jacoby 2NT is a 2NT response to partner's 1♥ or 1♠ opening that shows four or more trumps and at least game-forcing values. It asks opener to describe his hand: shortness first, then a good side suit, then his strength.

The idea is to agree the trump suit at once, below game, so both players have room to look for slam. You can see what 2NT over 1♠ means in every system. Jacoby 2NT is part of almost every 2/1 Game Force card, and Standard American Yellow Card (SAYC) plays it too. Acol players who use five-card majors often add it too.

Before Jacoby, a jump to 2NT over 1♥ or 1♠ was natural: a balanced invitational or game-forcing hand. Oswald Jacoby turned it into the strongest raise. After 1♠ - 2NT, both players know:

• Spades are trumps.
• The partnership is forced to at least game.
• Opener speaks next and describes his hand, so the stronger or more shapely hand is visible to the player who will make the slam decision.

That last point is the big benefit. A direct jump to 4♠ says nothing about slam, and a splinter shows only responder's hand. Jacoby 2NT lets opener tell responder exactly where his shortness is and how strong he is.

To bid Jacoby 2NT you need:

1. Four or more cards in opener's major.
2. Game-forcing values: an opening hand, about 13 or more points counting shape.
3. No singleton or void, in most partnerships. With shortness and support, a splinter bid describes the hand better.
4. Not a passed hand. A passed hand cannot have game-forcing values, so 2NT after a pass means something else (often natural, or replaced by Drury).

There is no upper limit. Jacoby 2NT is the start of every strong raise, from a plain 13-count up to a hand that wants to bid a grand slam.

Opener's rebids follow a fixed priority. These are the usual 2/1 ranges, the same as in SAYC; other partnerships move the numbers a little.

Opener shows shortness first, even with a strong hand, because shortness is the most useful slam information. The other bids come only when opener has no singleton or void.

After 1♠ - 2NT - 3♦, opener has a singleton or void in diamonds. Now responder looks at his own diamonds:

• Small cards (like ♦8732): perfect. Opener's shortness covers your losers, and all your values are working elsewhere. Think slam.
• Honors (like ♦KQ5): wasted. Your king and queen face a singleton and will rarely take tricks. Sign off in 4♠ unless you have plenty to spare.
• The ace: still useful, because it wins the first round, but the ♦K behind it is not.

Over the shortness bid, responder signs off with 4 of the major, cue bids a control to show interest, or asks for key cards with Roman Key Card Blackwood.

With no shortness, opener shows his strength:

• 4 of the major is the weakest bid. It says "minimum, no shortness, I have nothing more to say". Responder passes unless his own hand is strong enough for slam on its own.
• 3NT shows a medium hand with no shortness. Responder can sign off in game or start cue bidding.
• 3 of the major shows a maximum and is the strongest rebid, even though it is the lowest. Using the lowest bid for the strongest hand leaves the most room to explore slam. The jump to game is the weak bid: a principle called "fast arrival".

A jump to four of a new suit, such as 1♥ - 2NT - 4♦, shows a strong five-card diamond suit, usually with two of the top three honors. With a top honor or a fit in that suit, responder should think slam; without help there, he can sign off in 4 of the major.

Partner opens 1♠. You are South with ♠K865, ♥AQ4, ♦9762, ♣KQ: four trumps and 14 HCP. You bid 2NT. Partner shows a diamond singleton with 3♦.

Your diamonds are four small, so none of your values are wasted. You hold the ♥A and the ♣KQ, so the other side suits are covered, and opener's shortness means the defense can take at most one diamond. You ask for key cards with 4NT. Partner shows two with the trump queen (5♠), and you bid 6♠.

The slam has only 28 HCP, yet it loses just one diamond. North ruffs the other diamonds, and the trumps, hearts and clubs supply the rest. Give South the ♦KQ instead of two small diamonds and the hand is much worse: those honors fall under the singleton, and a trick disappears. The 3♦ rebid is what told South the difference.

1. Bidding 2NT with three trumps. Partner will expect four. With three-card support and game values, bid a new suit first (in 2/1, a game-forcing two-level response) and support later.
2. Bidding 2NT with a singleton. Splinter instead. Your shortness is the most useful thing to show.
3. Opener jumping to game with a good hand. 4 of the major is the weakest rebid. With extras, bid 3 of the major or 3NT.
4. Opener skipping the shortness to show strength. Shortness comes first.
5. Using Jacoby by a passed hand. It cannot be game forcing, so it is off.

• Range swaps. Some pairs play 3NT as the maximum and 3 of the major as the medium hand, or use 3 of the major for any hand with extras. Agree which.
• Relays. Some expert pairs replace the standard rebids with step bids that show opener's shape in more detail.
• In competition. After an overcall, Jacoby 2NT is usually off: a cue bid of the opponents' suit shows a limit raise or better. After a takeout double, a 2NT response often shows a limit raise or better in opener's major (Jordan or Truscott 2NT).
• Over minor openings. Jacoby 2NT applies only to major-suit openings. Over 1♣ or 1♦, 2NT is natural in most systems, and inverted minors handle the strong minor raise.

The best way to learn when shortness helps and when it hurts is to see many complete deals. The BridgeDummy Bidding Room lets you bid random hands with EPBot robots playing 2/1 Game Force or SAYC, and you see all four hands when the board ends. Our bidding puzzles then test single slam-or-game decisions, scored double dummy over many deals that fit the auction.

• Splinter bids: the raise to use when responder has the shortness.
• Limit raises: the invitational major raise.
• Bergen raises: four-card raises below game.
• Slam bidding: the full slam toolkit.