Suppose you are third hand, and your partner leads the seven of clubs, Dummy lays down the Q 9 2, and you hold A J 3, thus:—
Deducting seven from eleven, you find it leaves four. These four cards, higher than the one lead, are all in sight, Q 9 in Dummy; A J in your own hand, therefore the declarer cannot have any card higher than the seven. If he has, your partner’s lead is not his fourth-best, as you will see if you lay out the cards.
RETURNING SUITS. When the third hand returns his partner’s suit, he should lead the higher of two cards, and the lowest of three, unless he has a card which will beat anything Dummy may hold in the suit, in which case he should always beat Dummy.
PLAYING AGAINST DUMMY. Some of the fine points in bridge arise in situations which require a careful consideration of the Dummy’s cards.
There are three great principles in playing against Dummy:—
1st. Lead through the strong suits, and up to the weak.
2nd. Do not lead through a fourchette.
3rd. Do not lead up to a tenace.
These rules must not be blindly followed in every instance. They are simply general principles, and some of the prettiest coups arise from the exceptional cases.