[straube]

We've agreed to double as penalty after 1N P P, even against strong NT. I've never played this.

When would I want to double here? Like which vulnerabilities and what strength range?

If my hand is too strong, partner will pull...plus my points are sitting under the strong NT.

If my hand is too weak, responder may have close to an invite.

[sasioc]

I also have this agreement but have never had clear discussions about exactly what hands to do it on, so I'm interested to see what the replies say. It has come up a grand total of once for me when, at favourable, I doubled a strong 1NT in pass out with a decent 5332 15 count, hoping that the range change worked like it did when doubling a weak NT. The consensus amongst the people I asked was that I was light but not massively so and that, given that the 1NT bidder was a weak declarer, it was probably OK. Dummy hit with a 4 count and I misdefended ridiculously to let him out for 1100.

[gnasher]

The term "penalty double" is a bit misleading here. When we double 1NT, we're making a descriptive call, not expressing an opinion about how many tricks they'll make.

I double on any balanced 15-count, or a bit less at matchpoints, and it seems to work OK.

If partner has a weak hand and pulls to a 5-card suit, that's usually better than defending 1NT undoubled, because his long trumps will be tricks, whereas in 1NT we won't often be able to get to his winners. If partner has a scattering of high cards we'll be defending 1NTx with the right lead and an entryless dummy, so being under declarer won't matter much. If dummy is the one with the missing points and partner has no where to run to it will be a disaster, but that's a similar risk to the one we face when we double 1NT in second.

[whereagles]

Penalty dbl a strong NT on the balancing seat seems like a bad idea to me. If you have a flattish 15+, you're ok with any lead pard makes, so why bid and risk have pard pull this (as he will on a regular basis)?

[FrancesHinden]

As gnasher says, calling it 'penalties' is a mis-description. It works well if you play double as meaning either "I have a strong NT" or "I have a seriously strong hand". Second seat bids on the assumption that you have the first hand type; you show the second by bidding again.

The advantage of this is that
- you take a penalty when you have two balanced hands and the majority of the points
- you compete the partscore when partner has a weak distributional hand

[benlessard]

IMO doubling/overbidding with a strong balanced when you have a strong nt behind you is a beginner mistake, being in front rather than behind is just not the same thing. Use the double for something else, anything else.

[Raff90]

Why not playing takeout doubles in last seat? :-/.
I dont even like penalty doubles behind the 1NT opening

[ArtK78]

If you are going to make a penalty double of 1NT in passout seat, it should be based on having 7 or more tricks, not a balanced 15 count.

Now, if you want to play a strength showing double of 1NT in passout seat, that is an entirely different thing.