Stance of Clarity p. 66
You focus your efforts on a single opponent, studying his moves and preparing an attack. Your other opponents fade from sight as your mind locks onto your target.
This stance allows you to focus on a single opponent to the exclusion of all others. You read your foe's fighting stance, his favored attacks, and the methods he used to train. By combining these factors into a single analysis of his abilities, you see how to foil his attacks.
While you are in this stance, you must choose a single opponent as your target at the start of your turn. You gain a +2 insight bonus to AC against that foe until you change the target of this stance. You take a -2 penalty to AC against all other opponents while using stance of clarity.