Why Take A losing Finesse?

Why Take A losing Finesse?

This deal was played (and usually misplayed) in the biggest money event of the year, the 2017 Cavendish Pairs (played in Monaco). With neither side vulnerable, South held:

K98654
♥ 1096
♦ A9
♣ A8.

North dealt and opened 1 and you respond 1. LHO overcalls 1NT. This shows roughly 15-18 and stoppers in the bid suits (unless it is alerted as light takeout or something else). Opener makes a Support Double (announcing 3-card spade support). RHO shows clubs and you end proceedings by jumping to 4. A low club is led and you see:

J107
♥ K75
♦ KQJ854
♣ 9
K98654
♥ 1096
♦ A9
♣ A8

Your only potential losers are in spades and hearts. Thankfully, you have escaped a heart lead. On the low club lead, East plays the 10 and you win the ace. Most declarers now played reflexively, but incorrectly. They ruffed a club to dummy and led the J for a finesse that surely would fail. In fact, the jack lost to the queen and West shifted to the A and then played the Q to knock out dummy's king. Declarer couldn't play more spades (LHO would win and cash the setting trick). In desperation, he started the diamonds. Maybe three rounds would live (if RHO started with a singleton spade and short diamonds). No luck. On the third diamond, RHO ruffed with a small trump. Declarer overruffed, but the contract had to fail. This was the Real Deal:

Vul:None
Dlr: North
J107
♥ K75
♦ KQJ854
♣ 9
AQ
♥ AQJ8
♦ 762
♣ K754
32
♥ 432
♦ 103
♣ QJ10632
K98654
♥ 1096
♦ A9
♣ A8

Based on the bidding and trick one, West was marked with pretty much every HCP he held. With KQ, he would have led the K (wouldn't you)? So, when East plays the 10, you know East has QJ10 and West for his 1NT overcall, the K and all the other missing HCP.

Knowing the Q is wrong, the deal plays itself. There is no need to take the fatal club ruff at trick two (which took out a key entry to dummy at the wrong time). At trick two, declarer should simply lead a low spade out of his hand. West wins and shifts to the ace and queen of hearts. Declarer wins, but now is in control. He starts running diamonds, but this time he is okay when East ruffs the third round. Declarer overruffs and now takes his club ruff to reach dummy. He plays the fourth round of diamonds, throwing his losing heart while West remains with only the singleton A.