Bridge by Frank Stewart
"I played West for the ace of clubs because of his delayed double," South said.
Before South takes a view in clubs, he needs information. He leads a diamond to the king at Trick Three and then a diamond to his ten. Suppose West takes the jack and shifts to a club.
South knows that West, who passed as dealer, has the A-J of diamonds. If South plays the jack of clubs and finds East with the queen and West with the ace, South will still be confident of 10 tricks by winning the heart finesse. Most Wests would have opened with 2, K 10 9 2, A J 5 2, A 10 8 2 (and if West had the jack of hearts also, he surely would have opened). So South must play the jack of clubs.