Insightful Strike p. 63
You study your opponent and spot a weak point in her armor. With a quick, decisive strike, you take advantage of this weakness with a devastating attack.
Your mind rather than your physical power allows you to deal grievous injuries to your foes. When you attack, your training and mental focus allow you to score a telling blow. As part of this maneuver, make a melee attack. If this attack hits, you do not deal normal damage. Instead, you make a Concentration check and deal damage equal to the check result. Your Strength modifier, your weapon's magical properties (if any), and any other extra damage you normally deal do not modify this check (including extra damage from class abilities, feats, or spells).
If the melee attack roll was a critical threat, and you confirmed it, multiply the Concentration check's results by your weapon's critical modifier.