At first glance, making this slam just seemed too easy, but even so Declarer needed to plan his whole campaign before charging into battle.  It was a mistake to draw two rounds of trumps right away, as now Declarer could not draw the last trump (that would have let the defense score a Heart and a Diamond).   Trying to escape that grisly fate, he ruffed a Heart on the board and exited with the ♦K.  But that didn’t work, either.  East won the ♦A and returned a Diamond which had to be won in Dummy.  Now Declarer had no way back to his hand to draw that last enemy trump.  He led a third round of Diamonds but, when East followed to the third round, Declarer knew that his goose is cooked.  Whether he ruffed high or low, West’s ♠J would score a trick.  Down one!  What was the winning line?

►