For the 5th consecutive month, we visit a misplayed deal from the 2018 U.S. Team Trials. Watching online can frustrate me, as I expect more from the expert players. South held:
AKQ 
Q75 
AKQJ5 
J9
Vulnerable against not, he opened 2 and (after partner's 2 waiting) rebid 2NT to show 22-24 balanced. Partner used Stayman and then jumped to 5NT to offer a choice of slams. South chose diamonds, but North was having none of that and corrected to 6NT. A low diamond was led:
| J97 K1096 98 AQ54 |
| AKQ Q75 AKQJ5 J9 |
Dummy's 9 held. What are the odds? You don't need to know them! You just need good logic. Can you figure out the best line of play (note: there is no 100% line)?
Start by counting top tricks. You have 3 spades, 5 diamonds and 1 club. One big conclusion is that you should disregard the club suit. Even if you were to win a club finesse, that would get you to only 10 tricks. You could later establish a sure heart trick, but would still need to find the J for a 12th trick.
Since you will have to find the J regardless, there is no reason to take an initial club finesse. Contrast the club finesse plan to working on hearts (the right play). If you can find the J (which you will always need) and take 3 heart tricks, you won't need a club finesse. You'd have the 9 top tricks mentioned above and 3 heart tricks. So, it is only a question of how to play hearts.
You can finesse against either opponent for the J, but you should choose to finesse against West (LHO). Why? Because if he has the J (a 50% chance), you claim 12 tricks. If you play East (RHO) for it and he has it, you are not home free. You'd still need a reasonable heart break or club finesse. Picture, for example, East with Jxxx or AJxx. You'd lead the 10 for a finesse, but later, the Q and another heart would reveal the suit isn't running.
At trick 2 (in dummy), lead a low heart (East could have a singleton jack). No matter who has the ace, take the 50-50 finesse against West's J. Nothing (certainly stay away from the clubs) is better. This was the Real Deal:
| Vul:Both Dlr: North |
J97 K1096 98 AQ54 |
|
| 104 AJ842 1074 K102 |
86532 3 632 8763 |
|
| AKQ Q75 AKQJ5 J9 |
Declarer did actually work on hearts, but he played them incorrectly (running the 10 from dummy) for down one. The other table played in game, so this cost 26 IMPs (lose 13 instead of winning the same number).