But West did the right thing by shifting to the diamond queen.

The diamond queen was led and won with the king.

Now South had to work out which opponent held the diamond queen.

East thought he had to keep all his black cards and gave up the diamond queen.

If East has the diamond queen, he wouldn't break open the suit.

West won with his diamond queen and led a second club to South's king.

South ran this to his jack and led the diamond queen.

The diamond queen was continued and taken by the king.

South won with the ace and led the diamond queen.

If he had made the routine lead of the diamond queen, all would have been well for the defense.