Jacoby 2NT


Jacoby 2N is an artificial game-forcing (13+ total/support points) response to 1 with 4-card support. As such, it is also useful when playing 2-Over-1 Forcing. Jacoby 2N is off in competition or if the 2N bidder ("responder") is a passed hand.

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The purpose of Jacoby 2N is to get opener to describe his hand. Since Jacoby 2N is a game force, the only reason to bid it is to see if a slam is possible due to a good fit.

Many people say that the priority is showing a singleton or void, but ACBLsays that showing a good 5-card side suit is preferable (by bidding it on the 4 level). Also to be considered is that if opener bids a 2nd 5-card suit, he must, by definition (or simple math), have shortness in one of the unbid suits, so... 2 birds, 1 stone.

If it is critical for responder to know exactly which suit is short after, say, 1-2N, 4, he can bid the lower suit (4 in this example). If that is the short suit, opener can rebid his major; otherwise, he can bid the short suit (e.g.: 4). However, remember that you are giving that information to the defenders, too.

In the deal shown, opener bids 3 to show the diamond shortness. It would be nice if the K were in another suit, but even so, the DDA at the bottom shows that 6 can be made (if declarer guesses the Q right).

Responder, himself, would show a singleton or void by making a Splinter bid with 13-15 points, so the 2N bid denies such a hand.  
Another problem which has surfaced with showing shortness is that some sources say it requires 13+ points which makes sense because the point of showing shortness is that if partner has 19+ points and/or a highly distributional hand which may make slam with the right shortness in opener's hand.
This seems a lot less likely if opener has fewer than 13 points. 
At the same time, if opener has a hand like JT7-A98652-A75-Q, it only has 11 points because a singleton Q is not counted for its honor value, just the 2 points for the singleton. it doesn't fit any of the responses below with the normal requirement that 4 denies a short suit. 
To adjust for this, BidBase has an exception that 4 can be bid with shortness if the hand has fewer than 13 points.

Rebids by Opener

Points specified below are total points (HCP + distribution).

There are different methods for rebids by opener.  
Here is the default convention used in BidBase: 

  • 3 = singleton or void in Clubs, 13+ points
  • 3 = singleton or void in Diamonds. 13+ points
  • 3 = 15+ points and 6+ Hearts if Hearts were opened.
          = singleton or void in Hearts if Spades were opened. 13+ points
  • 3 = ditto, but vice-versa.
  • 3N = 15+ points, 5 or poor 6-card suit, no singleton or void.
  • 4 = 5+ Clubs with 5+ HCP in Clubs
  • 4 = 5+ Diamonds with 5+ HCP in Diamonds
  • 4 = <15 points, sign-off if Hearts were opened.
    It shows no short suits or a short suit but with < 13 points.
          = 5+ Hearts if Spades were opened.

Here is a second method which can be selected in BidBase: 

  • Bid 3 of a suit in which you have a singleton.
  • Bid 4 of a suit in which you have a void.

  • With no singleton or void, show your strength as follows: 
    • Bid 4 of your suit with <14 points and no slam interest.
    • Bid 3N with 14-15 points.
    • Bid 3 of your suit with 16+ points.

  • For example, after you open 1 and partner responds 2N, your rebids mean... 
    • 3// = singleton in the suit bid
    • 4// = void in the suit bid. 
    • 4 = <14 points, no singleton or void.
    • 3N = 14-15 points, no singleton or void:
    • 3 = 16+ points, no singleton or void.

Here is the Larry Cohen version:

    1-P-2N-P-?? (where is opener's major)
    • 4 = "the absolute worst dreck imaginable (always 5-3-3-2)"
    • 3 = a more respectable minimum (still could be 5-3-3-2)
    • 3 = non-minimum with a side singleton or void
    • 3 = non-minimum, any 5-4-2-2.
    • 3 = non-minimum, 6+ trumps, no singletons or voids.
    • 3N = non-minimum, 18-19 points
    • 4// = 5-card suit with at least A or K
    • 4 = sign-off

    If responder has slam interest:

    • After opener's 3, responder bids 3; opener responds:
      • 4 of opener's major = "5-3-3-2, minimum but not total dreck"
      • 3 = minimum with unspecified singleton or void
      • 3 = minimum, 5-4-2-2
      • 3N = minimum, 6+ trumps, no singleton or void
      • 4 of new suit = minimum, decent 5-card side suit with A or K
    • After opener's 3, responder bids 3; opener responds:
      • 3 = an unspecified void
      • 4// = singleton in suit bid
    • After opener's 3, responder bids 3; opener responds:
      • 4// = 4 cards in suit bid.
    • If opponent interferes after the 2N bid:

    Click Cohen's link above to read his explanation and rationale for this convention. An important statement is... 

      Like any new convention, this can't be taken lightly. Practice and study are required.
      I am not big on conventions, but this one is worth the effort for a serious partnership.

The odds of Jacoby 2NT coming up for a pair in a 27-board tournament is about once in every 4.5 tournaments, according to the CardShark BidBase Practice program.