[helene_t]

Long time ago, Fred posted an example of an auction that is difficult if you play weak NT:

1m-(2♥)-x-(pass)
2NT

Since responder has to do something with a random 9-count, the double is not about spades. Opener has to clarify their shape and strength, so 2NT just shows a balanced 15-16 count. It may or may not have spades.

If you play 4-card majors it is not a problem - opener won't have four spades in a balanced hand so 2♠ shows a minimum with spades and longer clubs, while 2NT would deny spades.

How do you play this 2NT rebid if you play weak NT and 5-card majors?

[LBengtsson]

I have tried to work out the logic behind this, and I guess that if I have to play a 4M system with weak NT, I open the 4M instead of a short minor suit with a 15-16 count hand. So, I guess also logically, with a 5M system that cannot happen, and opener can have 5(6)m4M hand or a balanced one? So bidding 2♠ here could be balanced hand (15-16) with no ♥ stop and 4♠, or 5(6)m4♠ with a minimum hand? Is that why this sequence is difficult?

And bidding 2NT shows...I would think 15-16 balanced and a ♥ stop but not 4♠? That seems sensible, but what if you have 15-16 without ♥ stop and < 4♠ hand. Eureka! I understand why now you have posted this on the forum helene_t. I will let other people who play 5m/weak NT to comment as that is not what I play.

[helene_t]

Yes 3343 without a heart stopper is also a problem if dbl doesn't promise four spades so 2sp could be a 3-3 fit.

But the issue is primarily about balanced hands with a 4card spades.

[akwoo]

1) The double "promises" 4 spades.

2) Opener will bid 2S with a balanced 15-16 count with only 3 spades and no heart stopper.

3) Responder has room to clarify after opener's 2S bid. Responder never passes with a 9 count and a heart stopper. The 2S bid by opener is not more wide ranging than in 1m-1S-2S.

4) I'm a K-Ser. Acolites may have different reactions.

[DavidKok]

I thought this is a Good/Bad 2NT situation. Also it matters a great deal to me which minor was opened, but I guess that depends on system.

If you play weak NT the 8-9 HCP responders have the extra option of raising to 3m with 4-card support, so the double is more descriptive.

[helene_t]

DavidKok, on 2022-April-10, 12:28, said:

I thought this is a Good/Bad 2NT situation.

I wonder - if 2NT is g/b, we will not be able to stop in 2NT when we have 15+8 points or so. Would you say that the negative double is GF opposite a balanced 15-count?

[nullve]

How about

1♦-(2♠)-X = GF opposite MAX, takeout

and

1♦-(2♠)-X; ?:

P = allowed (based on LoTT)
2N = Good/Bad
...3♣ = P/C
......P/3♦/♥ = badMIN*, NAT
......3♠ = MAX, 4 H, S stopper
......3N = MAX, < 4 H, S stopper
......(...)
...(...)
3♣/♦/♥ = goodMIN, NAT
3♠ = MAX, 4 H, no S stopper
3N = MAX, < 4 H, no S stopper
(...)

where

badMIN = "11-13" (unBAL)
goodMIN = "14-16" unBAL or 15-17 BAL
MAX = "17+" unBAL or 18-19 BAL

+ similar structures after

1♦-(2♥)

and

1♣-(2M)

?

* I need to invent the Badminton convention, obviously

[DavidKok]

helene_t, on 2022-April-10, 14:59, said:

I wonder - if 2NT is g/b, we will not be able to stop in 2NT when we have 15+8 points or so. Would you say that the negative double is GF opposite a balanced 15-count?

I don't play a weak NT, so I really don't know. I've always been told that it's OK to raise to 3m with, say, 8-9 points, support or tolerance and no descriptive bid. Either partner is unbalanced and you'll hit a nice fit, or partner has got a strong notrump and can take a view (pass on power/3NT to make/3♥ stopper ask, for example). I think it's not even crazy to raise on 3-card support - as long as you don't look silly opposite the weak unbalanced option, you can make a lot of moves. Once you take those hands out the double should show all of:

• Shortness in their suit.
  
• Shortness in partner's minor suit.
  
• No 5c♠ (over 2♥)
  
• No GF values

On 1♣-(2♥)-?, double basically ends up showing hands like 4=2=5=2, 4=2=4=3 and maybe the occasional 3=2=4=4/3=2=5=3/4=3=4=2/3=3=4=3 or so with 8-11 points (I'd probably bid 3♣ with 3 spades and 3 clubs here, but maybe there's merit in splitting the 8-11 range? I haven't given this much thought). I think with double so narrowly defined opener can consider passing 2♥X over bidding 2NT natural - the classical argument for not using 2NT to play in competition. And one day it will cost, but the rest of the time you have smoother auctions on the 3-level for it. Arguably this is more important if partner opened 1♦, or if they overcalled 2♠.

That being said, preempts work. Typically on auctions like this something has to give. I usually sacrifice 2NT first, and then ask if anything else has to go as well.

[paulg]

Most strong Acol players that I know open a four-card minor rather than a four-card major with balanced hands, so this is not just a problem for five-card majors players.

However none of them think it is a problem. They just bid 2♠ with four spades. It is analogous to 1m-1♠-2♠ in a non-competitive auction. You either have a strong no trump or an unbalanced hand with spades and a minor.