JACOBY 2NT ("Original")

(Click here for more advanced "modified" version)

Most tournament players use "JACOBY 2NT" in conjunction with their 5-card major system. After an opening of 1-MAJ, a jump to 2NT is conventional. It promises a GF hand and at least 4-card support. 

This convention should not be used by a passed hand and should not be used if there is interference by the opponents. I can't warn you enough how important it is when employing any convention to cover this vital issue (on by PH?--on in comp?).

In the "original" (most popular, stilll) version of this convention, this is the schedule of rebids for the opener after the Jacoby 2NT response:

4 of the trump suit=minimum, no shortness

3 of the trump suit=non-minimum, no shortness
3 of a new suit = shortness (singleton or void)
3NT=varying ways to play this, sometimes a sixth card in your major
4 of a new suit = good side 5-card suit (some people instead use this to show a void)

At any point, by either player, bidding 4-of-the-major which was opened is always the weakest (sign-off) action.

Other bids after the Jacoby 2NT and opener's rebid are control-bids-- this can be a singleton (or void), ace or king.

My suggestion is that you learn those 3-level bids, and don't worry much about the 4-level bids as those tend to make auctions more difficult. It can be very helpful to know where a singleton is when you have a 9-card fit. For example, look at these two hands: 

KQ987  8  A932  K87

A654  976  K5  AQJ4

 

 

 

 

 

 

 

North opens 1 and South uses Jacoby 2NT with a 14-count. North's heart singleton is tremendously helpful for South. Look at how all of South's cards are working. Now, South can envision this excellent slam with only 26HCP combined. 

INTERFERENCE:

As stated above, this convention is never on if they interfere after our 1MAJ opening. However, we do need to cope if they interfere after the 2NT response:

Opener's double = Shortness in suit doubled
Opener's new suits = natural or a control
3NT = Balanced Maximum (Ace or King in their suit)
Opener's Pass = Nothing special--flat hand, could be 5-3-3-2 awful after which, responder's X=penalty
Opener's jump to 4M = dead minimum, but 6-3-2-2

 

Mike Lawrence Webinar on Jacoby 2NT

 

Updated: Jan 2023