[Stephen Tu]

MP, everyone non-vul.
♠Kx♥QJxx♦Txx♣Jxxx
(1♣)-1♦-(1♥)-2♦;
(dbl)(1)-5♦-(5♥)-?
(1) support

[mikeh]

No

In fairness, a good part of the reason is that I have no idea what partner is doing. His auction seems weird to me. A simple non-space-consuming 1-level overcall, a modest raise by me and then he bids 5♦?

Maybe he is 4=7 pointeds or something and was hoping to be able to back into spades but decided that with his heart void and the fit he'd better jam the auction. But I am guessing.

In any event, my thinking is that our auction is so weird on its face that it is unlikely to be the field sequence. I expect relatively few people to play 5♥. I don't expect that we need to or can 'protect' a plus in 5♦.

If they have 11 tricks, doubling is wrong and if they have 10, doubling is probably unnecessary if all we are looking for is a good board as opposed to a tied-for-top. Add in that we haven't beaten them yet and that doubling may guide them in the play, and pass seems a standout to me.

But I collect more undoubled undertricks than most

[Winstonm]

Whatever partner has he has forced the opps into a guess and it appears they have guessed wrong. I don't expect 5H to make but I doubt if it needs to be doubled in order to be a good result.

[whereagles]

There is no guarantee of a set. Unless pard is very undisciplined (sort of guy who preempts once, twice and THRICE), I would just pass, trusting pard to realize the job of putting opps in no-man's land is done.

[ggwhiz]

Given that a double is odds on to turn 2 heart tricks into one or otherwise cost a trick in the play undoubled -2 = doubled -1 as your usual "upside" at an unnecessary risk. That risk goes to partners morale too if they were being umm creative.

[WesleyC]

Firstly, I agree with all of the other posters who have suggested that +50 or +100 is probably already going to be a good score. If you're playing in a pickup partnership, pass is probably the safest choice.

However playing with one of my regular partners, the auction defines their hand really tightly. They have something close to 4072 shape, and decent values. With a weak hand like [xxxx --- AQJxxxx xx] they would simply preempt 4D. Hands like [Axxx --- KQxxxxx Qx] or [QJxx --- AQJxxxx xx] are consistent with partner's bidding.

RHO is marked with only a 6 card heart suit so presumably also short diamonds. Something like [5602, 4603 or 3604] looks most likely, which leaves declarer with [2335, 3334 or 4333], possibly even with some wasted values in diamonds. Even if dummy has Hxx of hearts, they still have to negotiate bad breaks in both black suits while retaining trump control and avoiding a spade ruff. It just isn't going to happen. Also it's also not impossible for partner to have [AQxx --- AQJxxxx xx] where 5D is a lucky make and RHO was just messing around. Especially if RHO was known to overbid, I would trust partner and double.