mycroft, on 2013-December-16, 15:49, said:
(I don't know their runout methods, but if you double with this hand, we'll play 2♦X for what looks like 5 tricks. 6 if the defence is not careful. 4 if declarer isn't careful).
Far from clear what happens in any method IMO. If they're playing natural retreats (or exit xfers), responder might pass or pull in desperation, probably to 2C (although 2S might be better for the higher risk of them Xing you into game - jackpot if the defence can find the X here). If 2C, then the doubler probably shouldn't be able to allow a penalty X (or penalty) pass on a hand like this*, or he'll be losing out on several more moderate trump splits where Xing is the best action, so we'll have to 'rescue' them, ending up in one game or another.
Alternatively he might pass, allowing opener to bid 2D - though opener with a poor long suit and honours in the short ones might pass, hoping his P has a scattering of values. Again, jackpot for the defence - esp if they find a better lead than mine.
Or a third possibility, responder might just try 2C planning to pull to 2S if it gets Xed, which one way or another will get pulled to 2S before it reaches him, and the doublers will end in game.
If they're playing some sort of forced XX system, then responder can prob show Cs and (Hs or Ss), so opener will prob leave him in 2C, and again the doubler will have to pull.
If they're playing a non-forcing pass then they probably don't have a two-suiter offer that includes Cs, so responder will have to either pass or treat his hand as a single-suiter, in which case see above.
* But possibly the vulnerabilty should mean that a penalty X/pass is only made in extreme cases, but I'm not sure whether that means sitting the X/making a 'takeout' X should have some values in the suit instead. If you have the former understanding and can penalise 2C, it's hard to know if opener should pull to 2D. He's likely to have a 5-2 fit, but it's hardly the stuff dreams are made of. If he does, then a penalty pass of opener's 2D surely looks more likely since both defenders can envisage at least one more trump in their P's hand.