The bell guard is the part of a
fencing weapon that protects your weapon
hand.
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The "(" is the bell guard.
The bell guard varies in size for the three modern weapons...
In foil, the guard is pretty small--doesn't really even cover all
of the hand.
In epee, the bell guard is about twice the size, as the hand is a
perfectly legal target. And, being closest to your opponent, it is
aimed for quite frequently.
The sabre bell guard is about the same size as the epee one, but
it actually curves around and attaches to the end of the weapon.
This is to protect the top of your hand as well as the front as sabre is
a slashing weapon (making the hand a lot easier to hit).