MODIFIED JACOBY 2NT (for ADVANCED-EXPERT LEVEL)

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" version of this convention, this is the schedule of responses:

4-trump suit=minimum, no shortness
3-trump suit=non-minimum, no shortness
3-new suit = shortness
3NT=varying ways to play this
4-new suit = good side 5-card suit (some people instead use this to show a void)

Below is a version I played with my regular partner, David Berkowitz. Many top experts have adopted a similar schedule. I will reveal the advantages at the end (if you get that far).

MODIFIED JACOBY 2NT

After our 1-MAJ opening and 2NT response (Game-Forcing 4+-card raise):

4 of our MAJOR = the absolute worst dreck imaginable (always 5-3-3-2)
3 = any other minimum (could be 5-3-3-2, but at least some redeeming feature)
3 = non-minimum, with a side singleton or void somewhere
3 = non-minimum, any 5-4-2-2 distribution
3 = non-minimum, 6+ trumps (no singletons or voids)
3NT = non-min., 5-3-3-2 (you can use this to show a HCP range such as 18-19)
4 new suit = decent 5-card side suit (nat.--should have ace or king)

Follow-ups:

If responder ever jumps to game in the major, it is a sign-off--no further interest.

If responder still has slam interest, he can ask further as follows:

AFTER opener's 3 :

Responder bids 3 to ask, then (note the similarity to the original responses by opener):
4 of our MAJOR = 5-3-3-2 min., but not total dreck (maybe nice controls)
3 = minimum, with a side singleton or void somewhere
3 = minimum, any 5-4-2-2 distribution
3NT = minimum, 6+ trumps (no singletons or voids)
4 new suit = min., decent 5-card side suit (natural--should have ace or king)
(After opener's 3 or 3 answer to 3, next step asks, using same schedule as below)

AFTER opener's 3:

Responder bids 3 to ask, then:
Step 1=A VOID somewhere
Step 2= singleton in lowest side suit ()
Step 3 = singleton in next side suit ()
Step 4 = singleton in highest side suit (other major)
After Step 1 (VOID)
Next bid asks where and S1=, S2=, S3=other major

AFTER opener's 3:

Responder bids 3 to ask, then:
Step 1= 4 cards in lowest side suit ()
Step 2 = 4 cards in next side suit ()
Step 3 = 4 cards in highest side suit (other major)

This looks a bit complex, but there isn't too much memory. The first set of answers to 2NT must be memorized. After that, the same principle covers all the memory: Next step asks, and answers are "up-the-line."

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 5x3x2 awful after which, responder's X=penalty
Opener's jump to 4M = dead minimum, but 6x3x2
If they double Asks or re-asks : XX = business, Pass=S1, etc.
If they bid after Ask or re-ask : X=Penalty, Pass=S1, etc. (except when double = short as above)

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. Not only does it provide more accuracy, but the biggest payoff is in concealment. Most times, opener will have a minimum (12 points are statistically more likely than 15 or 19). When opener bids 3 to announce a minimum, most times responder will no longer be interested in slam. He will simply jump to sign-off in game. Meanwhile, you have not given away opener's shape to the opponents. It is too easy to lead and defend against standard Jacoby 2NT, when you are told opener has a singleton. It is much better to keep this information concealed on most deals.