South opened One Spade and a long and unconvincing auction led to Six Spades and left West with an unattractive lead. A club lead could, and would, lose a trick; it was easy to envisage hands where a trump or heart lead would be expensive, so finally West selected the king of diamonds.
Now, once the trumps were not 5-0, it was all over. As you can see, a lead in either major suit would have proved perfectly safe and would, superficially at any rate, have left declarer with only 11 winners.
It was not very likely that South would have followed dummy's suggested line of play, which involved leaving trumps alone for the time being (to keep an extra entry to dummy), playing three rounds of hearts to discard a diamond and eventually trumping a diamond in hand to establish the 13th diamond for a club discard.
Indeed, a very practical (but losing) line of play would have been to draw trumps and simply take two finesses in diamonds - a 75 per cent chance and one that would have avoided any deep thinking.
As the cards lie, with West holding all the outstanding strength, playing off five rounds of spades and three of hearts leaves West in great difficulty. His final discard will be from #KQ6 2QJ8 and, if declarer reads the situation correctly, leads to South's 12th trick.Reuse content