The tackle occupies the most important position on the rush line. It is possible to get along with a lumbering center and slow guards if they are able to block well and make good openings, but it is not possible to have slow tackles and play good football at the same time. The position which the tackle occupies in the line explains this, and it is best appreciated when it is understood that the tackles should take part in more than half the defensive work of the team.

The tackle occupies the most responsible position because he assists in checking two distinctly different styles of play. On the side toward the center he is to help the guard in blocking the heavy plunges which are frequently aimed at that point of the line, while on the other side he has to work with the end-rusher against all plays between them and on all plays around the end. To play this position properly on the defensive, therefore, requires a master mind and an equipment of physical capacity and skill unequaled by any position on the eleven.

Next to the half-back the tackle, from his position in the line, has the best opportunity for running with the ball. In fact, he can be used with telling effect, if a good runner, in supplementing and resting the half-backs. Again, he is the end-rusher's chief assistant in going down the field on all kicks, and he must be under the ball almost as soon as the end himself, in order to prevent the catcher from dodging inside the end men.

The points mentioned are sufficient to show that the tackle should be a man of considerable weight, because he has to bear a great deal of the heavy plunging into the line. The greater the weight the better, provided, of course, that the other requirements are met. As a rule, it is rare that a man weighing over one hundred and eighty pounds can meet these requirements, and it is more often that men weighing one hundred and sixty-five or seventy pounds are selected for this position on the best teams. The general build of the man also qualifies his usefulness. The one hundred and sixty-five pounds will be much more effective in a man from five feet six to five feet ten inches in height than in one above that height. In truth, the man of stocky build can usually fill this position much better, because his weight is nearer the ground and he is always in a position to make a low tackle. As a great deal of his tackling should be dashing and brilliant, right in the midst of interference where he must throw himself instantly, a tall man would be at a disadvantage. A thick-set, round-bodied man with large arms and legs would also be a much harder man to stop when running with the ball.

Of equal importance with weight, the points which should determine the selection of the tackle are agility, speed, and the ability to tackle in the face of interference. The name of the position indicates the work of the player. He is to tackle. Even speed can to a small degree be dispensed with if the man is quick and agile and is a sure tackier. Quickness in getting through the line, agility in avoiding interference, sure tackling, getting down the field on a kick, and running with the ball are essential qualifications to look for in selecting a man to fill the position of tackle.

The tackle must be endowed with more than the ordinary amount of shrewdness and judgment. To a certain extent this can be acquired by long practice, but the tackle must be of quick perception and good judgment naturally in order to play the position in the best manner.

When acting on the defensive the distance which he should stand from the guard and the manner of going through the line, either to the inside or outside of his opponent, should be determined by previous judgment as to where the play is to be made and influenced by an instantaneous perception as the play starts. The position, too, must be taken with the utmost caution and selected at just the right distance from the guard to best meet the play and still be able to defend his position on either side. There is need of the closest and quickest observation and cleverest judgment.

Moreover, as many of the plays cannot be determined beforehand, such a position must be taken as will best enable the tackle to check any play which can be made. He must then be on the alert for the very first indications of the play and act on them, and at the same time he must still keep the closest watch for later developments which change the direction in which the ball will finally be carried.

Playing up close to the guard is always dangerous unless it is necessary to do so in order to stop a wedge play, for the tackle could then be blocked in very easily from helping, if an attack were made on the space between himself and the end man, or in a play around the end. He therefore would cut himself off from defending two-thirds of his territory and the most defenseless part of the line. Playing far away from the guard is also dangerous, for he then leaves the part of his territory which is nearest the opposing half-backs too much exposed and gives his opponent a chance to block him off from defending it. Of course, if the tackle were free from the checking of an opponent, he could play some distance away from the guard and still defend the space between them; but the fact that there is a player opposite who is giving all his attention, wit, and energy to securing an advantage over him, gives a turn to the problem which he cannot ignore in making his calculations. The tackle takes a certain position; the opponent takes one also. It may be a little to the right or a little to the left of him, or it may be directly in front of him. The tackle may change his position a little and then the opponent perhaps change his, but their relative positions may, or may not, be changed; or possibly his opponent may remain in the same place. Just this action or inaction on the part of the opposing tackle is sufficient to help him determine how he should play in his defense, and is one of the signs to be considered in deciding upon his own position and action.