Fabris divides the sword into four equal sections, the first being the closest to the hand.
The first is the strongest and most useful for parries.
The second, while not as useful, can still be used if it meets in the opponent’s blade where it is weak.
The third is ineffective for parries and will only work if it is supported by the opponent’s body. (I’ve read about this before. Basically you stick the sword in the other person and as the blow comes in his own body absorbs the impact.)
The fourth part is utterly useless for parries, but is quite effective at wounding the opponent. Cuts should be thrown with the third and fourth parts, or roughly 1/4 of the way down from the tip. (Think “sweet-spot” from baseball.)
Conclusion: The lower-two sections are for defense and the upper two for offense.
Putting it into Practice
Using tape or some other highly visible marker, divide you sword into the four parts as described by Fabris. Then as you drill and spar note what parts of the blade you are using for cuts and parries.