Actually, Hiten Mitsurugi Ryu is a fictional school used by the character Kenshin Himura in the Japanese animation, Rurouni Kenshin, a.k.a. Samurai X. The technique in question is known as the Amakekeru Ryu no Hirameki, which was used by drawing a sakabatou (reverse blade sword) from the sheath while stepping forward with the left foot and using the torque of the body to slash diagonally up at tremendous speed. Although I'm not adept in Asian sword techniques, I don't believe there is much validity in the fact that stepping with the left-foot is the best maneuver. If you try it, you'll find it's a bit awkward. Anyone can correct me if I'm wrong.