About the rules of fencing

The three weapons are different not only by how the look like, but how they can be used properly.

First of all, the target areas are different:

In SABRE you can hit almost anywhere above the waist, including the head, back, chest and arms. Only the hands are not target area. (In the top left picture you can see Gourdain and Pozdniakov fencing at the Sydney olympics. Picture from verizon.net)

In FOIL you are aiming at the upper body, without the arms, hands and the head. Chest and back are target (Here the sentence 'Watch your back!' truly gains a meaning...)

EPEE is the weapon that wants it all: every inch of your body is target: head, back, chest, legs, arms, feet, hands... Toes, fingers... (Bottom picture, olympic fencing with a twist from the FIE homepage)

Secondly, there is the idea of the 'right of way'.

SABRE and FOIL are so-called conventional weapons, where the person starting an attack HAS PRIORITY over the other fencer. This means, that if your opponent attacks you, you must defend yourself first, THEN you can hit him. If you think about it, it is logical: you must be safe first before you can do anything else. This also helps keep fencing beautiful and elegant: fencers must think and act, and not just waggle their swords against you! If you attack, you can be sure to score a valid hit if your opponent just sticks his arm out to stop you, without touching your blade.

EPEE again, is different... Whoever hits first, will score the point. The trick is, that speed is not enough! If you attack, you must make sure that you don't expose any target area, because points can be given double: if you both hit, you both score (which can be dangerous if you are 4-3 down in a match up to 5 hits!).