When it is your fate to open a numerically weak suit, your object should be to do as little harm as possible. You cannot expect to win many tricks, so you must do all you can to assist orstrengthenyour partner by leading high or strengthening cards; for, by leading the highest of a suit numerically weak, you take the best chance of keeping the strength in your partner's hand, should he happen to hold it.
You will not often be driven to open a weak suit originally, as one of your suits must contain as many as four cards. But it may so turn out that your four-card suit is composed of very small cards indeed, in which case you might prefer to open a suit containing better cards, though numerically weaker. Every one can see that ace, king, queen, is a better suit to open than five, four, three, two; but, as you descend in one scale and ascend in the other, there comes a point where the two descriptions of strength nearly or quite balance. With hands containing only a suit of four small cards—say none higher than the seven or eight, and suits of three cards of higher value—the choice is sometimes difficult. Also, with hands in which your only four-card suit is the trump suit, you might sometimes deem it advisable to open one of the other suits, as a smaller evil than leading a trump. As a rule, when you are in doubt, stick to the general principle, and lead from your four-card suit, even though it is the trump suit.
Whenever you decide on opening a suit of but three cards, choose, if possible, one in which you hold a sequence which may be of benefit to your partner, as queen, knave, ten; queen, knave, and one small one; knave, ten, and one other, and so on, and lead the highest. If you have no sequence, lead from your strongest weak suit. Thus, two honours not in sequence, and one small one, is a better lead than ace and two small ones, or king and two small ones. These, again, should be chosen in preference to queen and two small ones. When leading from a numerically weak suit that contains ace, king, or queen, but no sequence, if you have any indication from the previous play that your partner is strong in the suit (as will be explained in Section 4), lead the highest. But having no guide as to his strength lead the lowest. You run the risk of making your partner think you have led from numerical strength; but, on the other hand, by leading out the high card, you at once give up the command of the suit, and, unless your partner has strength in it (the chances being against this), you leave yourself at the mercy of the opponents.
The case is different with numerically weak suits headed by a knave or a lower card. Of these suits you should lead the highest; by retaining such a card as the knave you would scarcely ever be able to stop the adversaries from establishing the suit, should they be strong in it; and, by leading out the high card, you do all you can to aid your partner, should he have strength.
Ace and one other, king and one other, or queen and one other, are very bad suits to lead from. Byholding them up you and your partner stand a better chance of making tricks in the suit; and if it should be the adversaries' suit (the chances being two to one that it is) you keep the power of obstructing it and of obtaining the lead at advanced periods of the hand. If you lead from ace, king only, lead ace, then king.
It follows that when you lead a high card in the first round of a suit, and in the next drop a lower one (subject to the rules respecting leads from sequences and the lead from suits of five or more cards), your partner should infer you have led from a weak suit. Thus, suppose you lead a nine, which is called an equivocal card, as it comes from both strong and weak suits. If in the second round your partner can infer that you hold a higher card, he knows you have led from strength. But if in the second round you lead (say) the eight, your partner may be equally certain that the former card was the highest of your weak suit.