Art. 1. Thou shalt not use thy fists in a duel, unless thou art a professional fist-fighting champion, certified by the Council of Elders. In that case, go for it.
Proceed to Rule 2: Thou Shalt Not Use Thy Feet
And then there's Rule 3: Thou Shalt Not Use Thy Face
But wait, there's more: Rule 4: Thou Shalt Not Use Thy Hair
And the pièce de résistance: Rule 5: Thou Shalt Not Use Any Other Body Part