lycier, on 2015-April-30, 05:55, said:
What's the exact meanings of this double? What's the exact name of this double?
It just like a conversation :
"Hi,pd,I make double only to show 13+TPs,don't promise 4-card other major."
The exact name is a "takeout double". A double that typically promises 3+ card support for all the other suits, and shortness (2-) in the opponent's suit. Occasionally different shapes with a hand too strong to overcall NT or make a simple overcall.
You seem to be under the impression that takeout doubles should promise 4 cards in the unbid major. This is too restrictive. If you require this, then you require North to pass with good hands with this sort of shape and 1-3-(45) shapes, and you will miss too many good games and partials when South has 5-6 hearts but not strong enough to act himself. The person short in the opponent's suit is the one that should act over preempts in marginal situations.
Yes, making takeout doubles with 3 cds only in the other major sometimes leads to 4-3 fits. This may or may not work out well. Often it works fine because you are doubling with shortness in the opp's suit, the tap is taken in the 3 cd trump hand, so you don't lose control. But sometimes the trumps are too bad and it doesn't work out. Good players realize that finding 5-3 and 6-3 heart fits that would not be found without the double more than compensates you for the losses from when the 4-3 fit doesn't work out.
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I'd say that this kind of double is not correct bidding expansion since actually this double only shows 13TPs without other meanings.
No, it did show 3-5 in the unbids and 2- spades.
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Due to the uncertainty of this kind of double,it is very easy for its follow-up to be in chaos.
This hand is just a evidence.
It follow-up is 3♠,is it a correct auction? Does bidding 3♠ depend on Hcp or TPs?
It's not chaos. It's just that 3
♠ is an overbid, and 3
♣ playing Lebensohl, showing approx 8-11, is perfectly fine.