StevenG, on May 14 2010, 11:42 AM, said:
Ace of spades followed by Jack. If declarer has the club Ace, he doesn't have a spade stop, otherwise East may still be able to set up his spades with the club Ace as an entry.
I think this is right. Partner has clearly ducked one of the minor suit aces hoping to maintain an entry to his long spades. Absent any UI, this is what I'm going to play as the only reasonable chance to set the hand.
Unfortunately, I don't know if this would be "obvious" to me without the UI concern. If partner tanked before passing out 1NT, I think (looking at my hand and dummy) that suggests long spades in a weak hand and I may be constrained from finding the spade switch.
If the UI is from partner's hesitation prior to ducking his ace, all that tells me is that he has that particular ace. I'm not going to set up any tricks for declarer by leading to that ace. I need to play a heart or a spade, and I don't see where knowing that partner has
♦A or
♣A helps me to decide which.