Choose an elemental damage type (fire, lightning, ice, acid, or sonic) when you choose this feat. You deal bonus 1d6 damage of the elemental damage type you have chosen during an iaijutsu strike. If you picked sonic, you instead only deal 1d4 bonus damage.

If you score a critical hit during an iaijutsu strike, you deal additional 1d10 of the elemental damage type you have chosen. If you picked sonic, you instead only deal 1d8 bonus damage.