The considerations that determine the most advantageous card to lead at the commencement of a hand differ from those which regulate the lead at other periods; for, at starting, the Doctrine of Probabilities is the only guide; while, as the hand advances, each player is able, with more or less certainty, to draw inferences as to the position of some of the remaining cards. The number of the inferences, and the certainty with which they can be drawn from the previous play, constantly increase; hence it not unfrequently happens that, towards the termination of a hand, the position of every material card is known.
In treating of the lead, it will be most convenient to begin by examining the principles which govern the original lead. The application of these principles will require to be somewhat modified in the case of trumps, as will appear hereafter.