[Liversidge]

Partner bid 1NT (weak) which was immediately doubled. I bid 2♠ with Kxxxx and nothing else. My LHO passed and partner bid 3S. We went 2 off. Partner justified her bid on the grounds of wanting to make it difficult for our opponents as we were playing Chicago rather than our usual duplicate format. I don't understand the reasoning.
I am not sure how many spades partner had but if she had four spades it could be argued that she was bidding to the level of the fit. Are there any circumstances where it is right to raise partner's takeout of a weak No Trump?

[helene_t]

Depends on the vulnerability but unless unfavorable I would raise with 4card support and a small doubleton. I would never raise with 3card support.

Beware of the 2♣ take-out, by the way. Some players use it with random weak balanced hand with only two clubs, planning to redouble if it gets doubled. And of course, if you have 5-card support you may suspect that partner intended it as Stayman or some other artificial bid which you haven't discussed (or you forgot about).

[The_Badger]

I admit I have never come across this before - ever! - and it's potentially more difficult to judge (I assume) given that an opponent has doubled, but many players use super accepts to transfers, without quite knowing why partner is transferring at the moment of using a super accept, so I have to agree with Helene that at favourable vulnerability there is a good case of raising with 4 card support and a doubleton.

[Liversidge]

 helene_t, on 2018-November-29, 13:17, said:

Depends on the vulnerability but unless unfavorable I would raise with 4card support and a small doubleton. I would never raise with 3card support.

 The_Badger, on 2018-November-29, 16:00, said:

I have to agree with Helene that at favourable vulnerability there is a good case of raising with 4 card support and a doubleton.

Suppose the bidding at favourable vulnerability went 1NT(weak) -(X)-2♠-(3♥) -?
Would the answer be the same, i.e. bid to the level of the fit, so pass with 3 spades and bid 3♠ with four spades?
And would the answer be the same regardless of whether we are playing duplicate or teams? Partner suggests that it pays to be a bit more aggressive when playing teams so bidding 3♠ with three spades is OK in this situation.

[helene_t]

 Liversidge, on 2018-November-30, 03:25, said:

Partner suggests that it pays to be a bit more aggressive when playing teams so bidding 3♠ with three spades is OK in this situation.

At teams you should be more aggressive bidding games but not more aggressive fighting for partscores. Here, you are unlikely to have game so 3♠ is aimed at winning the partscore fight. I don't see why such a bid should be made more aggresively at teams.

It might be ok bidding 3♠ with three spades and two hearts. But partner can be very weak and opps have a difficult choice to make about bidding game or not. Bidding 3♠ makes it easier for them as they can double it if they have the balance of the points and score decently without having to know whether they have game or not.

So I think it's better only to bid with 4-card support. Makes it also easier for partner to decide about a sac against 4♥.

[Tramticket]

 Liversidge, on 2018-November-29, 12:59, said:

Partner bid 1NT (weak) which was immediately doubled. I bid 2♠ with Kxxxx and nothing else. My LHO passed and partner bid 3S. We went 2 off. Partner justified her bid on the grounds of wanting to make it difficult for our opponents as we were playing Chicago rather than our usual duplicate format. I don't understand the reasoning.
I am not sure how many spades partner had but if she had four spades it could be argued that she was bidding to the level of the fit. Are there any circumstances where it is right to raise partner's takeout of a weak No Trump?

It would be a VERY rare action for me to ever bid after partner has made a weak take-out. I don't think I would ever do this at Chicago, playing for money! Or at IMPs.

It might be a reasonable gamble at pairs - particularly if you have opened 1NT with a five-card spade suit and will be protected by the LoTT. It is important to realise that a weak take-out might sometime be made on a four-card suit (but usually five with the spade suit.

Vulnerability is important as Helene says. The best time to compete for part-score is when both pairs are non-vul.

[hamish32]

3!S is correct when we stop them being able to bid game and the value of the penalty when they X us is less than the value of their game. Given partner can have zero or up to about 9 we cannot evaluate accuritly.

The way to think about it is that the weak 1NT was already a preempt. When they made the penalty X it put us on notice that they had our number. They will be able to penalise accuritly from here. So we should be delighted we have a 9 card fit and might get to play at the 2 level.

I guess i might bid 3!S green against red if i held sonething like: AKxx xx Kx KJT98. Which is a 1NT opener for my partnership.