[Bbradley62]

There was a fair bit of conversation on this a while back, and I don't know what changes were made, so I'm only including hands here that were played after GIB 19 was released.

I posted this one on Oct 26:

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South's 1NT rebid in competition shows 12-14.

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As always, ignoring South's lack of knowledge of GIB's convention card... South's 1NT rebid in competition shows 18-19.

Are these two auctions really that different? Aren't both Souths just trying to play, rather than defend, 1NT in an even-strength competitive auction?

[Mbodell]

I think they are quite different. In the second the opponents would have to compete to the 2 level to declare their contract, and your 1nt isn't taking any room away from them, so you could pass and then have them bid 2 red or bid 1nt and have them bid 2 red. In other words you've already forced them to the two level. In the first one it is possible that the opponents play 1♠. Therefore your bid might just be competitive forcing them to the 2 level. So I can see a reason to consider these two at least a little different from one another.

[cloa513]

Mbodell, on 2011-November-13, 00:36, said:

I think they are quite different. In the second the opponents would have to compete to the 2 level to declare their contract, and your 1nt isn't taking any room away from them, so you could pass and then have them bid 2 red or bid 1nt and have them bid 2 red. In other words you've already forced them to the two level. In the first one it is possible that the opponents play 1♠. Therefore your bid might just be competitive forcing them to the 2 level. So I can see a reason to consider these two at least a little different from one another.

It makes no sense to consider them differently. If you had 18-19 on the second hand, then you'd redouble spades and obviously North doesn't consider South to have that 18-19 in its memory as North-South must have far more than game values and either 3NT or simple double of 2♥ is the correct bid not expecting the opponents to keep ratcheting up their poor hand especially as E-W should also believe N-S have game values. It must be a rubbish description.

[barmar]

Redouble in the second auction would be a support redouble, showing 3 ♠, not extra values.

I think the difference between the two auctions is that a double usually shows a good hand, while overcalls don't. There's no need to bid with a minimum hand opposite a likely strong opponent. The missing piece in the bidding rule is that it's not distinguishing between a double by a passed opponent and an unpassed one. Once the opponent is limited, we shouldn't be scared to bid 1NT.

What's interesting is that 2NT also shows 18-19. There's a small difference, though: 2NT requires stoppers in the unbid suits, 1NT doesn't. I guess because you're reasonably safe on the 1 level without having everything stopped.

Interestingly, in the auction 1♥ (P) 1♠ (X) 1NT, it only shows 15-17. This looks like a leftover from before we allowed GIB to open 1NT with a 5-card major.

[Bbradley62]

I keep forgetting it while I'm playing, but I still think this is an error in GIB's bidding database. Since 1m-(p)-1M-(Dbl)-2NT shows 18-19, it can't be right for 1m-(p)-1M-(Dbl)-1NT to show the same strength hand (regardless of the stoppers difference). The 1NT rebid should be a minimum opener trying to declare rather than defend.

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[Areacode]

>> There was a fair bit of conversation on this a while back
I couldn't find the previous discussion.

At any rate, playing 2/1, 15-17 opening NT's and support doubles/redoubles, is it standard to treat opener's 1NT rebid as showing 18-19 in this auction?

1m-(P)-1M-(dbl)-1NT

[Stephen Tu]

I don't think it's standard.