Source: Play of the Hand: Playing Like the Hideous Hog
Trust the Opponents! Part I
We won’t always have such a ‘no lose’ option. Suppose we again reach 4
after this auction:
Even with the lead of the 
J, we still have a potential heart loser, the Q. We also have a diamond loser and two club losers. We could hope that East holds the 
K and bank everything on the diamond finesse. But do we have a better chance?
What do we make of West’s lead of the J? If we take it at face value, East must hold the Q. West has presumably led a singleton or from a doubleton headed by the J. That gives us a much better chance of making the contract. We can win the first trick with dummy’s K, planning to take a finesse against East’s Q.
We do have one problem, entries. Once we win dummy’s K, the only remaining entry to dummy is the K. We can’t take our heart finesse before drawing trumps, since West will ruff if the lead is from shortness. We’ll have to plan to draw trumps, ending in dummy.
So we win the K, take the A and Q, and then travel back to dummy with the K. When this draws all the defenders’ trumps, we confidently lead dummy’s 10 and take the finesse when East plays a low heart. Here’s the full deal:
When the 10 wins, we can repeat the finesse, leading the 4 and finessing our 9. We take ten tricks without needing the diamond finesse. We had to trust our instinct about West’s opening lead, since we gave up any chance of the diamond finesse when we used our last entry to dummy to take the heart finesse.
West made a perfectly reasonable lead. It was just unlucky that it gave us the clue to making the contract.
To be continued…