[gprentice]

If we open 1 heart or 1 spade (playing 2 over 1 and showing 5 card suit) and LHO bids 3C or 3D jump overcall, how does responder invite or compete or whatever i.e. what do 3 level and 4 level bids by responder mean and what does double by responder mean?

[Stephen Tu]

Normally:
Double = negative, usually 4 cds in the other major, occasionally not 4cds other major when too strong not to act and hoping partner can bid 3nt, and when you think you have something sensible to try if partner bids 4oM. But some people play "thrump" doubles instead emphasizing looking for 3nt instead of other major.
New suit = 5+, game force
Raise cheapest level (3M) = a decent raise, maybe 8-10ish.
Raise 4M = good 10- ~13/14 or so (have to overbid a little with limit raises since you want to raise 3 with lesser hands)
Cue bid = stronger than 4M, doesn't promise control of opp's suit. Exact boundary between 4M raise vs cue raise is fuzzy and subject to partnership agreement.

Jump new suit = probably needs partnership discussion, wouldn't assume anything, avoid without discussion.

[gprentice]

Great, thanks.

[gprentice]

We have decided to use the Thrump double. I found some information here - page 123
http://www.infobridg...temi_VMajor.pdf
that says the double shows game values and asks for a stop in the opponents suit. It also says that if the responder has an unbid 5 card major, they can bid that but it requires a stop in opponents suit as well - is that a reasonable way to play it ???

This article indicates that if the opener has a stop they bid 3NT, otherwise they can bid an unbid 4 card major.
https://www.bridgeha...rump_Double.htm

[Stephen Tu]

gprentice, on 2023-August-05, 17:40, said:

We have decided to use the Thrump double. I found some information here - page 123
http://www.infobridg...temi_VMajor.pdf
that says the double shows game values and asks for a stop in the opponents suit. It also says that if the responder has an unbid 5 card major, they can bid that but it requires a stop in opponents suit as well - is that a reasonable way to play it ???

I don't think that's what was intended as the meaning, though I could be wrong. That is an Italian site so I suspect the English isn't the best, it wasn't written as clearly as it could be. I think the idea is that with 5 cds unbid major you bid it, with or without a stopper. Since a major fit will often be more secure even if you do have a stop, often a single stop will be insufficient to make if there are opponent's cards to knock out in our suits. But you have to judge whether you can hold up and take hooks into the partner of the preemptor.

But with the opp's suit solidly double stopped, or if you have single stop, running suit + fast tricks outside, you should often forgo bidding an unbid major especially if above partner's opening suit, since you don't want to endplay partner into bypassing 3nt before you can bid it.

It would be crazy IMO to have to double with 5 or 6cd other major just because you don't have stop; if partner bids 3nt how would you know when to move?

The main thing is opener's rebid priority changes to bid 3nt with a stop vs bidding an unbid major.

[Gilithin]

The basic concept here is for Double to act the same way as a cue bid does in other auctions, a hand that is not yet sure of the right direction and wants more information. If you use it this way and bid hands with a definite direction naturally, you will have a workable basis to start out with. Unless you are running in particularly high circles, that is probably as far into the theory hole that you should delve at this stage.