[Jinksy]

1) What sort of hand do you expect from a competent doubler after the auction 1a P 1b X
1a) Does it make any difference if the b suit is spades?
2) How do most people play XX by opener? I’m a fan of mirroring responders XX bid after 1a X XX – ie extra points and no fit – but maybe that’s too infrequent on this sequence to be worthwhile?

[ArtK78]

(1) A hand with values and the unbid suits. If fourth seat has length in the unbids without values he can bid 1NT sandwich (if available) or 2NT. It makes no difference what suit b is.

(2) Some play a support redouble in this situation. Assuming it is not a support redouble, the redouble should show extras without a fit (with a fit opener can raise).

[mikeh]

Jinksy, on 2011-September-08, 09:13, said:

1) What sort of hand do you expect from a competent doubler after the auction 1a P 1b X
1a) Does it make any difference if the b suit is spades?
2) How do most people play XX by opener? I’m a fan of mirroring responders XX bid after 1a X XX – ie extra points and no fit – but maybe that’s too infrequent on this sequence to be worthwhile?

If you play support doubles, playing redouble as support can be useful, tho it's not as useful as the basic support double.

If not playing support redoubles, then playing the redouble as significant extras, without primary support for partner's suit is uesful since it sets the stage for a possible penalty double. If you play weak notrump, then the redouble can be a strong 1N or better: if you play strong 1N, then the 15-17 balanced hand doesn't exist, so presumably you have a better hand, which tends to reduce the bid's frequency.

[aguahombre]

mikeh, on 2011-September-08, 09:20, said:

if you play strong 1N, then the 15-17 balanced hand doesn't exist, so presumably you have a better hand, which tends to reduce the bid's frequency.

18-19 balanced and chose to hang around for penalty rather than rebid 2NT? I certainly agree that would be infrequent. Perhaps more frequent and useful would be unbalanced in the form of stiff or void in pard's responding suit (but 15+). Penalty oriented, of course; but more "informative" in nature.

[affe82]

I prefer support redoubles here. useful, especially since raise will show 4c sup.
We also allow the more infrequent really strong hand w/o support in redouble.
So, XX = a)interpreted as 3c sup for responder for competing purposes (frequent) b) a monster that will bid again (rare).

[Yu18772]

Jinksy, on 2011-September-08, 09:13, said:

1) What sort of hand do you expect from a competent doubler after the auction 1a P 1b X
1a) Does it make any difference if the b suit is spades?
2) How do most people play XX by opener? I'm a fan of mirroring responders XX bid after 1a X XX – ie extra points and no fit – but maybe that's too infrequent on this sequence to be worthwhile?

1)Shows values, at least 8-10 HCP (pending vul) in the unbid suits at least 4-4, not very distributional (5-5 or better is 1NT/cue/2NT - depending on agreements).
1a) If a is minor and b is spades, 5 card hearts is a real possibility, while if a is minor and b is hearts, 5 card spade is rare.
2) XX is3 card support, and 1NT (or any other bid) denies 3 cards in the responders suit. Some play it as support for b if b is major, and general extra on 1♣-P-1♦-X.

[FrancesHinden]

aguahombre, on 2011-September-08, 09:53, said:

18-19 balanced and chose to hang around for penalty rather than rebid 2NT? I certainly agree that would be infrequent. Perhaps more frequent and useful would be unbalanced in the form of stiff or void in pard's responding suit (but 15+). Penalty oriented, of course; but more "informative" in nature.

We had another thread recently about this.
If you play redouble as strong, then that frees up 2NT as artificial for example as a strong raise of partner's suit.
(and it's handy to play 1NT as 3-card support, rather than redouble)

[JLOGIC]

I play supp XXs in all my partnerships, mainly because I play strong club with my serious partners. Supp XXs are extremely common, I would assume them if we just agreed 2/1 udca, etc.

If you play XX as strong, then I would suggest using reverses as artificial also. EG: 1C p 1H X 2D = 3 card raise, 2N=strong 4 card raise, etc. If you have 2 reverses, play the lower one as a 3 card raise with 6 clubs.

As for what I expect from the double, it depends if they play sandwich NT. If not I think it can be quite a bit lighter than an opening bid if they're 5-5 and don't have a good hand to bid 2N, something like x Kxxxx KQxxx xx vul is fine for X to me. They can also be 5-4 with as little as a 10 count or so, or 4-4 with about an opening hand as a min. Form of game/vul, matters. It only matters if it's 1S in that they can often have 5 hearts, over 1C p 1H they will not have 5 spades that often. I guess the most marginal decision theoretically possible might pass spades but bid over hearts since its a bit safer, but it rarely if ever impacts my decision.