Nijūmon

Nijūmon (二重呪文, Double Incantation) is a specialized ninja skill known mostly by the skilled shinobi of the Naruto universe. As the name suggests, the skill consists of performing two at once, granting the user a great advantage in battle and allowing him to hold off several opponents at once. A more commonly known, yet more "primitive" variant of the skill is using two of the same jutsu simultaneously, demonstrated by in his fight with  and by  in  with. Naturally, this skill requires a great deal of, as the two techniques used together takes more energy then if they should be used separately.

However, real masters can use this to cast two entirely different jutsu at once, to overwhelm the opponent. In most cases, this also requires the user to be able to use one-handed in battle. Darui seems to be a master of this skill, being able to go even beyond two and use up to a total of four jutsu simultaneously.