Bare-handed combat

Combat Skill

Gives bonus to-hit and to-damage when no weapon is wielded. Can be used with weapon gauntlets.

You do not have to reach Grand Master level here before enhancing martial arts; that only needs enough training and free skill slots. What Grand Master level changes is the training: unarmed hits train bare-handed combat until it reaches Grand Master and train martial arts only after that, while kicks train martial arts at any time.