Source: [ilink url=”http://www.acbl.org/”]2006 ACBL Bulletins[/ilink]
Test your queen-placing in the following problems.
West leads the 
K and A, and East follows with the jack and 2. East ruffs the next club and leads a heart, and you grab the ace. Now if you can pick up the trumps, you can make your contract, pitching a heart on dummy’s Q. Who has
the 
Q?
West had four clubs and probably four hearts. If he had only three-card heart support, he might have preferred to rebid 1
with 4=3=2=4 pattern or 1NT with 3=3=3=4 pattern. West had at least three spades since East would have responded 1 with five. But if West’s distribution were 4= 4= 1 =4, he might have raised East’s 1
to 3 or at least competed to 3 over your 3. Play West for 3=4=1=4 shape and cashed the A K, expecting the queen to fall.
West leads the 4. East takes the ace and returns the J: queen, king. West then ponders and shifts to the J. Who has the Q?
Since West failed to continue spades and establish his long suit you can infer that he lacks a sure entry. (No doubt he should have continued spades anyway, but defenders make plays that look logical to them at the time.) Since East, who failed to open the bidding, has the A as well as the A J and, from West’s lead of the jack, the Q, play West for the Q.
West leads the 4, and East wins with the ace and shifts to the J. West takes the ace and returns the Q. To your dismay, East ruffs dummys king with the 5 and leads a heart. You ruff, and West plays the 8. You lead a trump – 10, A, 7 -and on the next trump, East follows with the 8. Who has the queen?
You can’t know for certain who has the Q, although some Wests would have overcalled with: Q 10 K 8 4 10 6 A Q 10 5 4 3 .
You’re going down unless diamonds break 3-3, giving you a discard for your club loser. (Since the play marks West with at least three hearts, a minor-suit squeeze on him is impossible.) Finesse with the J, hoping West started with
1=3=3=6 pattern.