Strike of the Broken Shield p. 74
You study your opponent and deliver an attack precisely aimed to ruin his defenses and force him to scramble for his balance. While he struggles to ready himself, he becomes more vulnerable to your attacks.
As part of this maneuver, make a single melee attack. This attack deals an extra 4d6 points of damage. In addition, the target must make a Reflex save (DC 14 + your Str modifier) or become flat-footed until the start of his next turn.