Answer to Double Dummy Problem

In this problem from You Have To See This (by Andrew Diosy and me)

The contract was 4♥ and the question was should you play or defend.

The opening lead was the ♣Q, overtaken with the ♣K and won in the South hand with the ♣A.

First, what happened to Helen Sobel.  At the other table her opponent drew trump in three rounds and played the diamonds from the top.  West won the ◊K and switched to a spade.  South needed to use the ◊J to discard a spade (or he would have 4 losers) but the only way to dummy was on a trump.  After taking the spade discard he still had to set up a club trick and he was now open to a force in spades and went down.  Helen tried a craftier play.  She led the ◊Q out of her hand at trick two.  When her opponent switched to a spade Helen was able to win the spade return, cash the ◊A and then play three rounds of trump ending in dummy.  Now she could take her spade discard and still have control of the hand.  Helen made the hand and that was how it was written up in 1998.

However the hand cannot be made on best defence.  After Helen concedes the ◊Q, West plays two more rounds of clubs, allowing East to discard a diamond and then get a diamond ruff from West.

So the answer to the question is: You would rather defend this hand.

It seems obvious to me now.  It is a warning that when you analyze hands to see if the hand could be made (or could be defeated) it is easy to miss something.  It is probably even easier to miss something when you are out drinking and discussing hands after the game!