CONTRACT: 3NT South
OPENING LEAD: 4 (4th best under an honor)
Six sure winners: two spades, two hearts, one diamond and one club.
Line of play: play the diamond suit for extra winners (rather than the club suit)
Trick 1 W: 4, 3, Q, K
Trick 2 S: J, K, 2, 4
It is tempting for South to win the ace and play for an overtrick: five diamonds, two spades, two hearts and one club.
This line of play will work if the diamonds split 3-3. However, a 2-4 split in favour of East will produce only three diamond tricks, declarer having no entry to dummy to cash the fifth diamond when established.
A safer line of play is to forget about the extra trick and let the diamond king win at trick two.
Following this safety play, declarer can now win any return and cash his nine winners by leading his last diamond toward dummy: two spades, two hearts, four diamonds and one club.
Declarer makes his contract.
The defense takes four tricks: the diamond king, two clubs and one trick in the majors.