Posted 2015-July-10, 04:25
I think we're reading way too much into pard's ♠2. Without going into the nuts and bolts too much:
We know partner has 2-4 hcp and thus one useful card - the ♠Q, ♦K or ♣A/K. I think declarer would remove 1NTX to a five-card suit if he had one, so partner has at least three spades. Long story short, I think we need partner to have at least four spades to the 10 to be setting this regardless of what card partner has.
I don't think we're setting this unless partner has the ♠Q (I leave it to the reader to work out why the other cards rate not to work). I'm exiting a spade - if declarer flies, we can cross to partner's ♥10 (or spot) to cash out. If declarer ducks, I cash out hearts and exit, prepared to dump the ♦QJ if declarer plays that suit.