3 Tricks from Kxxx opposite Qxxx

This came up yesterday in a practice session with Kathy on BridgeBaron.  You’re in a very dicey 3NT contract where you opened 1NT and your vulnerable LHO overcalled 2H (DONT, but it doesn’t really matter).  You need to get 3 tricks from the Diamond suit with this layout:

Dummy:  Q852

You: K976

What’s the best way to play this suit?  Your only chance for 3 tricks is if one of the players has a doubleton ace.  If you had X-ray glasses you’d see which opponent has this.  Lacking X-ray glasses or the hand record for the session, we’re going to presume LHO (the bidder) has it, so our presumed suit layout is this:


AJ, A10, or Ax                           J10x, Jxx, or 10xx


If you knew the cards were placed this way then the winning play is low to the Q and then duck a diamond to the now bare Ace.  When you’re playing the hand you don’t know for certain, but given the information available, this is the best chance to get your 3 tricks.