Source: [ilink url=”http://www.acbl.org/”]2006 ACBL Bulletins[/ilink]
Test your queen-placing in the following problems.
West leads the 
K and continues with the J; Q, A. On the next diamond West ruffs and shifts to a low spade to the 
4, K and A. You might have escaped with a plus by passing 2 doubled, but the bidding is over. If you can guess the 
Q, you can get out for down one at 3… , and minus 100 may be worth some matchpoints. Who has the Q?
West had two diamonds and only four spades since East needed three-card support for his raise to 2 . But if West had four hearts, he’d have responded 1
, showing his major suits “up the line.” So East’s pattern was 3-4-5-1. Cash the A and lead to the J, knowing the finesse will win unless East had 14 cards.
West leads the K and continues with the 2 to East’s ace. East then shifts to the 10. Who has the Q?
Give the opponents credit for logical defense. When West led the 2 at the second trick, East knew he’d started with four spades, leaving South with three. If East had Q-x-x in trumps, he’d have assured a set by leading a third spade and forcing dummy to ruff. Since East has given you a chance to finesse in trumps, don’t. Cash the A K, hoping West has Q-x .
West leads a low trump, and East takes the ace and shifts to the Q. Your king loses to West’s ace. East wins the next club with the 10 and leads the jack, and you ruff. You draw trumps, finding that West started with J-7-2. East throws a club. Next you cash the A and lead another heart, on which West plays the 10 and Q. On the J he discards a diamond, so who has the Q?
After the plodding auction North-South had, West would prefer a passive opening lead. A trump lead is usuall safe, but to lead from J- x- x could have saved declarer a guess or cost a trick outright. If West had a worthless diamond holding, he would often have led a diamond instead. Play West for the Q.