i think, but am no expert...
i think that guards are arms and whole body's positions used to prepare for easier defense or attack execution.
during Karate lessons i worked mostly with one, basic i think, Guard.
Legs spread a little, body position lowered a little, one foot forward, arms upward vertically covering chins and face parts, and upper torso. elbows close to each other.
i gained more moves, that i have unpracticed yet.
i work mostly with three positions of arms:
- basic guard i learned a little during Karate lessons,
- horizontal/vertical guard, good for capturing legs then striking faster, without needing to raise both arms fully before strike. it's lower arms position than above arms guard.
- extended forward arms guard, without clenching hands into fists. i think it can be useful for capturing weapons before they come too close to body, in an attempt of divert/dodge. whole body moves away to side, while arm diverts weapon's trajectory.
these three arms guards positions can be easily 'transitioned' from each to each and back, so i think it can be coherent style with enough of a practice.
perhaps there are more moves that i could use, but i prefer to work on basics first.