Yesterday, one of my favorite blogs posted this
hand, with the author suggesting that he didn’t see the best line yet. Here is my response, and attempt to do better.
You are in 5♦. In the auction, 3♠ showed spade values in an attempt to reach 3NT. 3NT is actually a reasonable contract, but it is hard to blame north for not bidding it and 5♦ is a better contract anyway. Against 5♦, west leads the ♠J to the ♠A. East returns a spade for your king, west following with the ♠2. That, and west’s pass over 2♠, suggests a 6-2 ♠-split. Over to you.
With a 2-1 trump split, the hand is easy. 2 rounds of trumps, ruff 2 clubs in dummy, claim. So, let’s assume that there is a 3-0 trump split either way. Would it be good to concede a heart at trick 3, trying to set up some sort of cross-ruff?
No, east-west can manage to win the trick in east and return a third round of spades. If you ruff low, west can overruff and you are down. If you ruff high and trumps split 3-0, you can no longer handle ♦J93 in either hand and score two club ruffs in the dummy without overruffs.
So, in trick 3, you cash the ♦A. If trumps split, claim as above. If west shows out, play ♣K, ♣A and try to ruff a club. If this gets overruffed, you are down, but then you cannot make the contract anyway, as it will be impossible to draw trumps and score two club ruffs. If east follows to the third round of clubs, play a small diamond to the ♦10, ruff a club with the ♦Q and play a heart. Eventually, you will score the 4 remaining tricks with ♦K1065. For this to work, east’s shape has to be 6-1-3-3 or 6-0-3-4. The latter is unlikely though, that would mean that west never bid holding 8 hearts to the ♥AKQ.
If east shows out, and west thus has 3 trumps, again play ♣K, ♣A and a club. It is unlikely that west will ruff the ♣K or ♣A, as this would have given him a 2-7-3-1 shape with ♥KQxxxxx or better. He’d probably have bid something, sometime. Ruffing the third round of clubs won’t do west any good, so let’s assume he discards a heart. You ruff in the dummy. Now the key play: ♠10 from the dummy, ♠Q, and a nice loser on loser play by discarding the ♥10 in this position.
East is helpless, if he returns a spade, you discard a club and overruff west’s card. If he returns a heart, you ruff, and lead a club. Now the ♦Q, heart ruff to the hand, ♦K and claim. A club return has the same effect. Overtaking by west does not help either. If west returns a diamond (best), run it to your hand, ruff a club with the ♦Q, ruff a heart, draw the remaining trump.
Now for the bonus point. Did you see how east could have defeated the contract? His hand was something like this: 
Not playing the ♠A at trick 1 will defeat the contract. South wins, plays the ♦A, ♣KA, ruffs a club and leads a spade from the dummy. East wins, cashes the ♥K and returns a spade. Now the loser on loser play doesn’t work anymore. Impossible to see?