Here's a lead problem from the 2009 Trials you are sure to get wrong
(maybe that will help you get it right?):
A 7 6 5 3
9 8 3 2
10 4 3
LHO, who is trailing late in the match, opens 2, strong. This is the auction:
What is your choice? Maybe partner's double is Lightner, asking for dummy's first suit. Could he be void in diamonds? But, declarer redoubled. No doubt, he is ready for a diamond lead. Or, maybe he is just redoubling because he trails in the match. Maybe you should try to cash your A first? This was the full deal:
A J 3
A K Q J 7 6 4
Q J 2
|A 7 6 5 3
9 8 3 2
10 4 3
|J 10 9 4 2
A K 9 5
|K Q 8
K Q 10 8 6 5 4
8 7 6
This deal knocked out the #3-seeded JOHN DIAMOND team. Note the team name. Diamonds was the suit led by Geoff Hampson. Declarer (Melih Ozdil) soon claimed all 13 tricks for a whopping score of 2940!
Of course, a club lead would have led to down two and a score of 1000 for E-W. How could West possibly know? (Maybe if he were playing for the "CLUB" team.? Maybe East thought the double was for dummy's first-bid "suit"--clubs. When the suit is artificial, this usually isn't the way a Lightner double is used.
In any event, with or without the double, I don't see how West could ever figure out to lead a club. At the other table in the match, East-West "sacrificed" in 6 doubled down 1,100. With a club lead against 7XX, DIAMOND would have won 19 IMPs. With the diamond lead, they lost 18 IMPs. A 37-IMP swing on opening lead!!!!
(For another huge swing on lead, see this article from 2006)