How to go down in 3NT

[rod]

Here's another instructive computer deal. After a routine Stayman auction you, South, are declaring 3NT with the ♦2 led. Scoring is IMPS.

North
♠ K93
♥ AJ93
♦ 865
♣ A64

South
♠ AQ62
♥ K64
♦ AQ
♣ 9532

East plays the ♦K. You have eight tricks with very good chances for a ninth. What do you do?

I'll tell you in advance that this program plays the cards pretty well, yet your computer opponent at the other table went down.

[rod]

The problem with testing the club suit is that even if diamonds split 4-4 as expected, you will not enjoy discarding on the last two rounds of diamonds. You can comfortably lose the lead once but not twice. So let's leave clubs alone.

Spades will split 3-3 or not, and if not you will need three heart tricks. Finessing twice in hearts gives you a 75% chance of that, but can you do better? Yes, you can play the Ace and then the King and lead up to the J9. This may give up an overtrick but wins whenever hearts are 3-3 and whenever the Q or 10 is onside.

Indeed, the opposing cards were:

West
♠ 85
♥ 752
♦ J972
♣ Q1087

East
♠ J1074
♥ Q108
♦ K1043
♣ KJ

[HDZ7]

God one Rod. With S J9 you have to first eliminate doubleton Q possibility in either oppornents, an if so you know that S are either 3-3 or 4-2. I would take this all the time, if I am in sound concentration state. Even if it is Jx I would do the same.