Suppose you are South in a teams game, and your two-no-trump opening is raised to slam. How would you play it on the spade 10 lead?
You start with 10 top tricks and should look to the club suit for two more. While there are decent lines of play that might generate an overtrick, you would not want to jeopardize your best line for the contract unless you were playing pairs and could be sure everyone would be in the same contract. (For the record, this might be one of those deals!)
A straightforward line of play will suffice whenever clubs are 3-2, or if the queen is onside. Can anything be done when East has Q-x-x-x in clubs?
There is a safety play available with this combination. Start clubs by leading toward the ace. If West followed with the nine or 10, lead another club and finesse the eight when East follows small. If West can win the trick, clubs are 3-2 and the slam is safe. It is when the club eight holds that you are ahead of the game: Unblock the club king and cross to dummy in diamonds to establish the long clubs. Of course, it can-not help East to split his club Q-9 on the second round.
This line would still be fine if the club Q-10-9-x were onside, since you would find out in time to put up the king on the second round and lead back toward dummy’s jack. Your approach only loses if West has all five clubs and hearts are 3-3 — much less likely than a singleton 10 or nine with West.