This Real Deal (slightly modified by me) is from the 2016 Spingold. South held:
AJ
J10754
A5
Q952.
At favorable vulnerability, his partner dealt and opened 1. South responded 1 and his partner rebid 2, Opposite a sound opening bidder, it would be okay to bid 3NT. In the Spingold match, both South players invited with 2NT (have you seen how light white-on-red opening bids can be these days)? At one table, opener passed, but at our table, he raises 2NT to 3NT. You get the 3 lead (Standard) and see:
K74
3
KJ9743
AJ10
|
| |
AJ
J10754
A5
Q952
|
With this lead, you have 3 sure spade tricks. RHO plays the 8 and you win the jack.
As usual, I advocate counting winners at notrump. You have only 6 sure tricks (3 spades, 2 diamonds and 1 club). If you take a club finesse and the suit behaves well that could get you to 9 tricks (you'd need the K onside and LHO to hold no more than 3 clubs).
Is there anything better?
Yes. The diamond suit. Only Q10xx(x) offside would prevent you from taking 5 diamond tricks. That has got to be a better chance than the club suit (which is at best 50-50).
If diamonds produce 5 tricks, you have 5 diamonds, 3 spades and the A. Yes, there is a slight danger of losing a diamond and 4 heart tricks, but more on that later.
At trick 2, you unblock the A (you did, didn't you?) and then play the A. It goes low, low, 10. That's pretty good news. You are now assured of at least 5 diamond tricks. On the next diamond, LHO plays low. Should you finesse?
Without getting into the psychology of the 10 (would RHO play it with 10x?), there is a clear reason to reject the finesse. It has to do with the heart suit.
With such a heart holding, you have to understand what layout would lead to you losing 4 heart tricks. The key is to realize that if LHO is on lead, you are completely safe. If LHO leads a high heart, all is well. If he leads a low heart to RHO, and a low heart comes back, you can split your jack-ten and LHO will be on lead. You will be protected. What if RHO is on lead to start hearts? Now, you could have a problem. RHO leads a low heart forcing your ten or jack. Then a low heart from LHO could go to RHO's honor and another heart could come through you. If LHO has four hearts with two honors, you could have troubles.
All of that reasoning in the heart suit (which becomes routine with experience) dictates your play in the diamond suit. You don't want RHO to win a diamond trick. If you finesse and lose to a doubleton queen (in this case Q10 doubleton), you could lose 4 heart tricks. Accordingly, you should go up with the K (if RHO has Q10x, you just have to hope for the best). East actually has Q10 doubleton and you can see what happens if you finesse:
Vul:E-W
Dlr: North |
K74
3
KJ9743
AJ10
|
|
Q6532
AQ82
862
3
|
|
1098
K96
Q10
K8764
|
| |
AJ
J10754
A5
Q952
|
|
After South won 2 spade tricks and played the A (drawing East's 10), he played a diamond to the king. The queen dropping just meant an overtrick. Had declarer finessed, he could have been defeated. Notice that East has to shift to the expert 9 to avoid blocking the suit (and West would have to read the position, winning his queen and returning a low one to the king).
