Seion

is a high-speed movement technique that allows the user to move at speeds faster than eye (both normal and Sharingan) can follow. Instead of channeling it throughout his body, Ryū Senju pumps his sound-nature-chakra to his feet, in huge quantity allowing it to carry him. He can not only use it to levitate himself a few feet above the air but also move at super-sonic speeds. Athough, the full extent of it's speed remains unknown but Ryū generally uses it to accelerate to speeds exceeding Mach 2. Once, a GORGON agent comment that Ryū with his technique can never catch Ryūken since Ryū's full speed should not be more than Mach 5.