INFERENCES FROM LOW CARD LEADS
An application of the Rule of Eleven will materially assist you to draw correct inferences from the lead of a small card. It will indicate whether the lead is from a short or a long suit.
If you see more high cards than the Rule of Eleven would allow, you can mark the lead, not as fourth best, but as the top of a short suit. If the lead indicates a long suit, you can often determine the exact combination of cards from which it has been made.
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.
The lead of an eight or a seven (except at no-trumps) is more apt to be from a short than from a long suit; combinations in which these cards would be fourth best are seldom opened by good players.
It will be easier for your partner to read your lead, if with long weak suits, headed by jack, ten, or nine, you lead the fourth best card. These cards can be led to indicate a short suit.
You can determine the length of your partner’s suit by noticing the fall of the low cards.
When it is evident that your partner has led the lowest card of his suit, his lead indicates exactly four cards. If your partner is leading from a long suit and plays down on the second round, he holds more than four cards.