This real deal was played in a downtown Chicago skyscraper as part of a practice match for a major event. South held:

J
A K 6 5
A 4
A 6 5 4 3 2
.  In 3rd seat he opened 1 and his partner responded 1. Now what?

I don't love reverse auctions, but this hand is good enough for a 2 bid. There are only 16 HCP, but they are beautiful points (aces and kings). Furthermore, the J might now be worth something since partner has bid spades. The 6-4 shape along with the other factors makes this hand barely worth a reverse (I just can't get myself to rebid 2 with this pretty hand).

After your 2, partner bids 4. This wasn't discussed (it was the opponents who were doing the practicing--you were just a fill-in pair). You guess to raise to 5 and see:

 

A Q 6 2 J 7 4 7 5 J 10 8 7

J A K 6 5 A 4 A 6 5 4 3 2

 

Not surprisingly, your auction has attracted a diamond lead (the queen). What is your plan?

If clubs are 3-0 (either way) there is nothing you can do to pick them up. Accordingly, there is no reason to lead clubs from the dummy (it can't help). So, after winning the first trick (holding up can't do you any good), you bang down the A.

Thankfully, everyone follows (the queen from LHO, the nine from RHO).  Now what?

At the table, South figured he had a diamond and likely a heart to lose. In addition there was a club loser. So, he tried a spade finesse. He led the J and LHO followed low. Would you let it run?

That was not South's intention. If the J won the trick, declarer would be in the wrong hand to discard his diamond loser. So, he overtook with the Q in dummy. Had it won, he would have thrown a diamond on the A and easily made his contract. This was the full deal:

 

 

Vul: Both Dlr: North	A Q 6 2 J 7 4 7 5 J 10 8 7
10 5 4 3 10 9 3 2 Q J 10 9 Q		K 9 8 7 Q 8 K 8 6 3 2 K 9
	J A K 6 5 A 4 A 6 5 4 3 2

As you can see, the spade finesse lost. East won and cashed a diamond. Because the Q fell doubleton, the contract was down only one.

 

 

Where did declarer go wrong?

He took his chances in the wrong order.

Winning the A and laying down the A was an okay start. But, before putting the contract up for grabs on the 50-50 spade finesse, declarer should have tried the hearts first.  If nothing good happens on the AK ("good" would mean the appearance of the Q), then there is surely a heart and club to lose. In that case, declarer would have to take a spade finesse for the contract. However, on the Real Deal, the Q comes tumbling down. With no heart to lose, declarer need not risk the spade finesse. He loses only a club and a diamond to make his 5 contract. By the way, nice job in the bidding to avoid the doomed 3NT.