Declarer can see dummy, but a defender can’t see his partner’s hand. To help each other, the defenders adhere to practices such as leading the top card in a sequential holding or fourth-highest from a broken holding. (Some partnerships use other methods.) The information is available to declarer as well.

Today’s West leads the deuce of spades against 3NT: jack, king, ace. South hopes for four clubs, four diamonds and the major-suit aces, but when he takes the A-K of clubs, West throws a heart. Then South needs four diamonds to make his game.

ONE CLUB

South takes the A-K — East-West follow — and leads a third diamond. West plays the nine. South should recall that West led the deuce of spades, showing a four-card holding, and had one club.

If West’s shape had been 4-5-3-1, his opening lead would have been a heart. So South should assume that West was 4-4-4-1 — and play dummy’s ten of diamonds.

DAILY QUESTION

You hold: ? A 8 4 ?A 10 4 ? K 7 4 ?A 7 6 3. Both sides vulnerable. The dealer, at your right, opens one diamond. What do you say?

ANSWER: This is a judgment call. Since the hand has good defensive values but a lack of winners, to pass and hope for a plus on defense might be a winning call. I believe most experts would double. If your partner has a suitable hand, you may have a game, and you will have trouble getting there if you don’t act immediately.