Clever tactics on the football field depend first of all on the captain's possessing an accurate knowledge of the strength and weakness of his team, both in individual play and in team play. This can all be acquired during practice by carefully noting every play which is made, and giving thought to the strength of the individual men and the value of the play in its relation to the others, both in regard to the perfection of execution and in intrinsic merit from a strategic point of view. It also depends upon the captain's observing as soon as he enters the field and throughout the game, the incidents of the day; the direction and force of the wind; the position of the sun; and the condition of every part of the field. All these points are of great importance in good generalship. Lastly, it depends upon the study which he makes of the way the opponents arrange themselves on the defense, as well as the style of their play when in possession of the ball. He must also seek to find out by trial which of his plays can be used most effectively.

Having the knowledge of the first and second requisites for good generalship, the captain must immediately proceed to find out the weakness and strength of the opponent's defense, not by trying each play in turn and just noting its success, but by using the best tactics the occasion demands, and closely-observing the result on each play. Every play known to be strong because of the ability to concentrate or mass the players at some part of the line, or for any other reason, should be tried at least two or three times early in the game in order to give it a fair test, that the captain may know which will be his most effective plays. It is a mistake to keep pounding away on two or three plays which give an advance of a few yards, just on that account, until after other reliable plays have been given a fair trial. In making this trial, the time should be well chosen, both as to position on the field and as to the number of the down, and the previous loss or gain, if it is the second or third down. It often happens that a powerful play is discarded because in one or two trials it did not work well. The difficulty may have been in its imperfect execution, or in a neglect of duty on the part of one man even, or it might result from the inability of one player to do his work because of circumstances or tactics on the part of his opponents which he could not overcome, but which, later on, he would discover a way to meet.

By confining the tactics to a few plays which have proved successful for more or less gain, the captain limits his play very decidedly and clearly indicates his policy, thereby giving his opponents a knowledge which is invaluable in thwarting him. The result will be that all the available players upon the opposing team will be called from the appointed positions where they had been placed in order to meet the most varied style of plays, and stationed where they can render these particular plays most ineffective. The knowledge that the play will probably be one of a few, also gives every player on the defense a certainty of action which will make his opposition very much stronger. The uncertainty which comes from combating a variety of tactics weakens each man's defense considerably, and puts him at his wit's end to discover what the play will be and how to meet it. It also makes him more liable to be blocked off and pocketed.

Sometimes, to be sure, it is fine strategy to keep pounding away at some particular point or points in the line, in order to draw the attention wholly to this place and to draw the men away from other parts of the line in order to weaken it for a sudden attack; but this is quite different from the limited style of play so often used, and really, if well done, is a mark of clever generalship.

The captain sometimes uses all his plays in succession simply because he has been accustomed to run through them in practice. This is poor tactics. If it has once been clearly proven that a certain play cannot for any reason be made, every clear-headed captain will realize that it is very, poor policy to waste downs in the effort.

A similar mistake sometimes grows out of giving the signals in practice. If the captain or quarter-back in giving the signal is not careful, he will get into the way of unconsciously arranging the plays according to the law of association of ideas, one play following another in unvarying sequence. The principle of sequence in plays would not be fatal, and, indeed, would sometimes be very effective, if the plays are well selected. But account should be taken of the physical capacity of the players; the duties which they have just been called on to perform; and the right time and place on the field, in reference to the side lines and nearness to the goal. The great advantage to be gained lies in having the sequence come in the form of a series which is perfectly learned, so that play after play shall be made in rapid succession. The series, however, should not consist of more than from four to six plays, as contingencies often arise which seriously injure their effectiveness. In any case the series ought to be stopped if for any reason it is unwise to make the next play, or if the conditions allow a much better move. A simple signal will indicate that the series is to be stopped. The great virtue in series plays lies in the fact that a certain signal starts the series and each play can be made in the quickest manner, because the players all know what is coming next and are ready the instant the ball is in the center-rusher's hands. Series plays are especially effective against a team which is slow in lining up. They are very valuable also in their moral effect, because of the rapidity and enthusiasm with which the plays are made.

Under a varied style of play where many movements are well executed, the opposing team must exercise the greatest headwork and caution in its defense. If the other team has not already indicated its policy by clearly denning its plays, every one on the opposing eleven will be conscious of so much uncertainty as to what the play will be, that his attack through the line is likely to be cautious and therefore not strong; or else it is likely to be sufficiently daring to give the opponents a decided advantage in making their plays. When undue caution is exercised on the defense, its effect often is to make the players hesitating. This, when extending throughout the rush line is fatal to a strong defensive game. A daring, reckless defense is far more effective than the cautious defense which makes a rush line hesitate, because of the moral effect on the other team, if for no other reason.