If in any doubt as to your lead select your longest and strongest suit and lead the 4th best.
WHY THE 4TH BEST CARD IS LED
There are two reasons for leading the 4th best card of your long suit.
To show partner how many cards you hold in the suit.
To show partner what you have in the suit.
If you lead 4th best and afterward either discard or play a smaller one, your partner will know that you originally held more than four cards in that suit. The lead of a deuce, for instance, shows but four cards in the suit. Your partner, by applying the "Rule of Eleven," can very often tell the exact combination of cards from which you have led.
THE RULE OF ELEVEN
Deduct the size of the card led from eleven, and the difference will show how many cards HIGHER than the one led are held outside the leader's hand. If, for instance, your partner lead an eight spot, the dummy having the queen and you holding A 10 x of the suit, as you see three cards above the eight, you know the dealer cannot play higher and that your partner must have led from K J 9 8.
| Q 6 2 (11 - 8 = 3) | ||||
| Y | ||||
| 8 | A | B | A 10 4 | |
| Z | ||||
This rule is especially important at "no-trump"; but players should not give it much attention unless the card originally led is higher than a five.