The N.C.A.A fencing tournament at Harvard this Friday and Saturday will provide an exhibition of the best in collegiate fencing, demonstrating all the manuevers of the sport.

A fencer in any of the three weapons--epee, foil and sabre--wins his bout by scoring five touches against the opponent. The method of making these touches differs, however, according to the weapon.

The target in sabre fencing is the whole front of the body as well as the upper third of the back. Touches may be made with the blade, as well as the point of the sabre. Therefore, sabre play tends to be flashier and more exciting to watch than is fencing with the other weapons.

In foil competition, the target is limited to the upper half of the front of the body; touches may be scored only with the point of the blade. Similarly, although the target in epee play is slightly bigger, only the point is used to score.

Because of the different targets and use of blade, epee and foil can be scored with electrical equipment, whereas sabre play must depend entirely on the decision of the judges.

In most intercollegiate play, each college enters three men in each weapon, each of whom fences, against all three opponents in that weapon. The 41 colleges participating in the N.C.A.A. tournament, however, will enter only one man for each weapon, who will fence against all 40 opponents in the same weapon.

Four bouts in each weapon, 12 bouts in all, will take place at the same time.