Rosenblum trump compound

[Andy]  It's my turn to blog on Franco's favorite subject.  The following is what will most likely be the most famous hand from the Rosenblum final.  (It was described in the NY Times today also, although I didn't see it online there yet.)

	♠ A 6 3
	♥ K J
	♦ A K 4 2
	♣ K 4 3 2
♠ Q J 4 2		♠ 10 9 7 5
♥ 8 3		♥ Q 9 2
♦ Q 8 7 6 5		♦ 10 3
♣ 9 8		♣ Q J 10 6
	♠ K 8
	♥ A 10 7 6 5 4
	♦ J 9
	♣ A 7 5

Zia got to 6♥ and received the ♠Q lead.  He found an elegant line, cashing his winners and taking 3 ruffs in his hand, then exiting with his last club.  In the end position he could claim regardless of the location of the ♥Q.

Moss and Gitelman did one better, though, arriving in 7♥.  I'm not sure what happened, unless Gitelman intentionally bid a grand on a blackwood auction in hopes that the opening lead would reveal the trump Q.  (This is a somewhat well-known trick, but definitely pretty gutsy in the last quarter of a world championship final that you are winning!)  Anyway, Rodwell did lead a trump, and Moss won the trump A, played trump to K, spade to K, drew the last trump, ruffed the third round of diamonds, played the second to last trump, unblocked clubs, and played the last trump to achieve a double squeeze (spades being the double threat suit).

That was very well done.  Let's take a look at the hand from a theoretical point of view.

With a reasonable number of entries, compound squeeze principles suggest that the contract should be makeable if one positional threat can be found.  It seems natural to hope that suit is diamonds, since declarer can isolate it, and the club threat needs to be in his hand.  Moss' line probably would not have worked had Rodwell held something like ♠J x x  ♥x x  ♦Q x x x x ♣ Q 10 x.  Rodwell would probably unguard spades and keep clubs in that layout, and Moss would not have the timing to unblock the ♠A to achieve a double squeeze around clubs.  (This is necessary since the extra spade winner gives Rodwell an idle card.)

So to achieve full compound generality, declarer appears to need to preserve the ♠K in his hand.  Perhaps declarer could take the diamond ruff before drawing the last trump.  This would leave two entries in both black suits and guarantee a working compound position as long as Rodwell held at least 4 diamonds.  Of course, it might lose if diamonds were 6-1 and RHO could ruff.  It might also lose if LHO overruffs in a position where there was just a minor suit squeeze against RHO the whole time.

An intriguing variant is to start the way Moss did, but play the 4th trump before taking the diamond ruff.  I think that also guarantees the ability to make the contract any time LHO has at least 4 diamonds.  The triple squeeze part of the compound is achieved at that point, since there is a ruff-out threat in diamonds.  Then, if LHO unguards spades at that point and declarer can read it, he can unblock the ♠A before taking the diamond ruff.  If LHO guards spades then the play continues as it actually did at the table.  Cool!