Kuuenzan

Kuuenzan or Kūenzan (空円斬? lit. "Air Circling Slash"), is one of the two special techniques that Zero learns after defeating Split Mushroom in Mega Man X4. By pressing the attack button while airborne, Zero preforms a circular slash with his Z-Saber. Once Zero learns Kūenzan, it permanently replaces his midair saber slash for the remainder of the game. Unlike his normal midair saber slash, Zero can famously change directions left and right for the duration of the slash, enabling some exploits for hits and damage.