You maneuver into an advantageous position and strike your foe with ruthless detemination.

Encounter
Minor Action      Personal

Effect: If you have combat advantage against a target, you deal +1d6 damage on the next attack you make against that target. You must apply this bonus before the end of your next turn.
    Increase extra damage to +2d6 at 11th level and +3d6 at 21st level.

Published in Monster Manual.