D&D4 Wiki

You practiced the basic motions of your discipline until they became as natural as breathing.

Prerequisite: Monk, Flurry of Blows class feature, Unarmed Combatant class feature

Benefit: You can use your Dexterity modifier instead of your Strength modifier for attack rolls and damage rolls when making a melee basic attack with your monk unarmed strike. In addition, your flurry of blows power can be triggered when you hit with an opportunity attack made with your monk unarmed strike.

Dragon Mag 404 pg 42