Many partnerships play support doubles without ever really having discussed standards. The purpose of this memo is to suggest standards for my fussy readers. who obsess on correctness and take all the adventure out of bridge. Support doubles and redoubles must be marked on your convention card and are alertable (join the club if you have a few “failure to alerts”.)
The essentials of every support double are partner must have opened 1club, 1 diamond or 1 heart and responder must have made a major suit response at the one level. You may make a support double on a minimum hand, but if you have both a minimum hand and only 3 small cards in support for partner, you may want to consider “pass”. Both Mike Lawrence and Eric Rodwell have said pass is an option with that holding.
It does not matter what opener’s LHO does in the auction as long as responder can bid his major suit at the one level. The sequence 1c/x/1s/2h is still a support double, the double showing 3 card suport for spades. Basically we ignore interference by LHO unless it prevents partner from showing his major suit at the one level. So 1c/1h/1s/2h/x is still a support double. Since responder chose not to make a negative double over opponents heart overcall, we know he has a 5 card spade suit, but he will still be happy to find opener with has 3+ card support. If opener had 4+ card support he would not make a support double. He would have bid some number of spades depending on the strength of his hand. With 4 card support, whether opener makes a simple bid, jump in partner’s suit or jump directly to game is based on the same considerations if there had been no bid on opener’s right.
In all situations where a double would show support, if RHO doubles responder’s overcall (it would always be for take-out) instead of making an overcall, a redouble of RHO’s double would show the same level of support as a support double. So, 1c/p/1s/x(take out for hearts and diamonds)/xx is a support redouble showing 3 card support for spades.
At what level does double of advancer’s bid cease to be a support double. Mike Lawrence suggests that as long as partner can still bid 2 of his suit after the double, it is always a support double. Thus doubling a cue bid by advancer (1c/1h/1s/2c/x) is still a support double showing 3 card support for spades. Mike Lawrence also does not have any trouble with 1c/1h/1s/1NT/x being a support double. He notes that while many old style player’s would say this double is for penalty, he prefers to treat it as a support double. In is nice to have a rule that is always consistent: responder can still bid 2 hearts in the above sequence.
So here is the rule. The double or redouble of RHO’s bid by opener shows support for responder’s bid major so long as responder can rebid his major at the 2 level. Effectively this means playing support double through bids of 2 hearts by RHO. This avoids partner having to play at the 3 level with only a 7 card fit.
What happens when the bidding gets higher than that? Say the auction goes 1c/1d/1s/3d/? Suppose as opener you held (i) KQxx, AQxx, x, Axxx, and the bidding proceeded as above. Here you have a nice 5 losing trick count hand and clearly would have made some kind of game try, but the bidding got too high for you to do so. Contrast this with (ii) QJxx, KQxx, xx, AJx, a 7 losing trick count hand, little defense against 3 diamonds and good support for partners bid major. With both hands you want to bid 3 spades, in the first case to invite partner to game and in the second solely to compete against the diamond contract. How does partner know what you want?
The opponents have taken away your bidding spade. At this point bidding 3 spades is compeititive and shows a hand like (i) above. The invitational bid disappeared. A double on the other hand is a penalty double, and may be the right call with hand (i) if the vulnerability is favorable, but my vote wold be to bid 4 spades. While only a 15 hcp hand, it had only 5 Losing trick Count (you read that blog, didn't you). Partner must have no more than 9 LTC for his 1 spade response, and making 10 tricks with a total of 14 LTC is a high probabliity.