[straube]

aguahombre, on May 5 2010, 07:39 PM, said:

so, the singleton is not shown by the opener directly, unless he has extras?

Yes, that's right. We had a very recent thread about this in the arficial bidding forum, but I was asking about J2N opposite limited hands. Still, you might get something out of it.

[aguahombre]

Well, all the answers have been helpful. We have gone far beyond what my "mentees" wanted to know.

But, since I trolled my own thread....am still looking for the incontrovertable argument that J2N is a good thing and is worth giving up other uses for 2N -- and other uses for 1NT followed by 3NT --- and natural 2C responses, in order to employ it.

[straube]

aguahombre, on May 5 2010, 09:08 PM, said:

Well, all the answers have been helpful. We have gone far beyond what my "mentees" wanted to know.

But, since I trolled my own thread....am still looking for the incontrovertable argument that J2N is a good thing and is worth giving up other uses for 2N -- and other uses for 1NT followed by 3NT --- and natural 2C responses, in order to employ it.

Certainly 2N is very preemptive compared to (say) a 2C artificial relay. One has a real job trying to organize opener's responses for maximum efficiency.

In its favor I suppose...

1) it establishes an immediate GF/fit which helps opener compete (if it looks right) to the 5-level if opponents interfere. It also allows for forcing passes, redoubles to show first round control of suits that opponents double, etc.

2) is a lawful asking bid in events where relays are not permitted. Opener (for example) can concentrate on showing various hand features instead of trying to find a fit.

3) differentiates 3 from 4 trump in responder's hand

4) usually establishes that responder is balanced (unless possibly too big to splinter) and means that responder has at least 2-cd defense for every suit and means that responder's cues will show A or K and not shortness.

[peachy]

aguahombre, on May 5 2010, 09:08 PM, said:

Well, all the answers have been helpful. We have gone far beyond what my "mentees" wanted to know.

But, since I trolled my own thread....am still looking for the incontrovertable argument that J2N is a good thing and is worth giving up other uses for 2N -- and other uses for 1NT followed by 3NT --- and natural 2C responses, in order to employ it.

The good thing about J2NT GF for your mentees is that it is commonly played by other same level players and it is part of SAYC, a common online and club system [if you call it a system, I guess].

Showing shortness on 3-level is mandatory in J2NT even with minimums, unless showing 5-5 on the 4-level - which of course also has shortness - when both suits are good. Even with its faults, J2NT is still better than old Goren GF raise 1S-3S.

[Mbodell]

gwnn, on May 5 2010, 12:14 PM, said:

standard, simplest and worst system is

3x singleton
3M max
3N medium
4x 55
4M min

so it's 3NT.

I play this in some partnerships, think it is the default standard I would assume with a pickup where we only ticked off J2NT and left it at that.

I'd leave the 4M rebid for bare bone minimums. Suitability for slam matters, obviously, so HCP is just a guide, but I'd think even in a standard system (where opening bids are usually 12+) I'd think 4M is at most bad 13s (you are talking about 7222, 6322, 5422 shapes only, and with the first two many 11 HCP will open something), 3nt is like good 13 to 16 and 3M is like good 16 and higher.

[ONEferBRID]

I've been told that "anything" is better than plain vanilla Jac2NT.

I favor Swedish2NT, but usually have to rely on Jac2NT with most.

A few comparisons:
Jac2NT is GF.

With Swedish,
Responder has 4 +, limit raise or better; so you can stop in 3M.

When Opener has a minimum, his rebid is:
Jacoby                    Swedish
4M ( no shortness)    3C! ( any minimum); 3D! then asks if shortness anywhere.

Jacoby: Opener shows shortness with ANY hand.
Swedish: direct shortness is shown ( over 2NT!) ONLY w/"extras";
otherwise indirect shortness is shown w/minimum hands only if subsequently asked for.

[Bbradley62]

gwnn, on May 5 2010, 04:14 PM, said:

standard, simplest and worst system is

3x singleton
3M max
3N medium
4x 55
4M min

These are standard responses to Jacoby 2NT. According to BBO's SAYC convention card, those are defined as:
3M=18+ HCP, no singleton or void
3NT=15-17 HCP, no singleton or void
4M = 12-14 HCP, no singleton or void
I think this isn't as useful as it could/should be.

I learned those descriptions (a couple of decades ago) as:
3M=would have invited or forced game over 1M-2M
3N=would have passed 1M-2M or bid 4M over 1M-3M
4M=would have passed a limit raise 1M-3M
These descriptions allow for a useful trade-off between HCP, extra trump length and other intangibles.

The point of this convention to (somewhat) quickly (and simply) determine whether slam is a possibility. If one of these is opener's rebid, responder should have a good idea now. If opener would have bid 1M-2M-4M and responder has a minimum for his 2N bid, it's possible that the auction will go 1M-2N-3M-4M-4N, which sounds strange, but it's still straight-forward.

The advantages are that it straight-forward and sufficiently standard that it requires almost no up-front conversation by pickup partnerships. Regular partnerships can easily modify it to their liking.

[aguahombre]

Y'all have convinced me. No J2n in casual partnership, and not with any Swedes. Plus I don't think I will give up compartmentalized bids of 2/1 to fit it in

[fromageGB]

aguahombre, on May 5 2010, 10:28 PM, said:

Ok, so in a J2N auction, is there ever a time when Responder relinquishes captaincy back to the opening bidder, having in any way described his(responder's) holding?

The way I play this, yes.
Our structure is a simple 1♠ 2NT ?
    3♣ = I don't have a shortage, do you?
    higher bids = show shortage
After 3♣ responder makes the same bids as opener to show his shortage if he has one.
If responder has no shortage either he can ask/describe strength.

If either party shows a shortage the other can then sign off or make further asks. So there is no concept of captaincy, as it is a mirrored situation. For us responder does not have to have a balanced hand. Our splinters are never more than minimum opening strength, so J2N is made with any 13+.

If responder has a shortage, opener is the captain. If opener has a shortage, then although the "wrong hand" is disclosed, I think it is better than not being in the correct contract. I suppose you could modify it so that if it is opener that has a shortage, responder then tells his features/values rather than ask opener's. A minimum (after devaluing holdings in the shortage suit) would sign off anyway.

(Note - to make a symmetric system, we play 1♥ 2♠ as the J2N)