This deal was reported by my friend, Victor Markowicz, from an event in Poland. In a team event, South held:

 AQ763  
 KQ2  
 AQJ10  
 7.

He opened 1 and partner responded 1NT. He rebid 2 and partner bid 2. He now "patterned out" with 3 and his partner put him in 4. How should you play on the 10 lead?

 

J2  A64  K64  86432

AQ763  KQ2  AQJ10  7

 Declarer, a world champion, won the K and played a low spade towards the jack. Do you agree? 

This was the real deal:

 

 

 

 

 

Vul:Both Dlr: South	J2  A64  K64  86432
109854  1098  93  AQ10		K  J753  8752  KJ95
	AQ763  KQ2  AQJ10  7

The jack lost to the king and declarer had no chance. 

Yes, the spade layout was unlucky, but declarer's play was wrong.

Here is the correct (by "rote") thought process for declarer:

1) If spades are 3-3 or 4-2, this contract will be easy. I can afford to lose 1 club and 2 spades. I will play the A and then a spade towards the jack. Let's say they win the king. I get back in and lay down the Q and make 10 or 11 tricks. If the J holds, I come to hand and play another spade, and make 4 or 5.

2) If spades are 5-1, I might have a problem. The defense can win the K and play clubs. I will lose 3 spade tricks and the A no matter which opponent started with king-fifth in spades. But, if spades are 5-1 with a singleton king, I can survive.

Accordingly, the correct play is to win the heart lead (in either hand) and play the A at trick two. Here, the king falls and declarer plays to the J, back to hand for the Q and then just runs winners. If the K doesn't fall, play another spade and make as long as they aren't 5-1.