Rurouni Kenshin: Meiji Kenkaku Romantan S02E15 - Between Life and Death

Kenshin undergoes training so that he can learn the ultimate technique. He barely manages to get in a hit against Seijuro in a bout, where he then learns "Kuzuryuusen,"a powerful technique that launches nine slashes at the same time. Kenshin learns to see through Seijuro's swift sword movements and masters "Kuzuryuusen" by looking at it only once. However, the technique was only born out of the process of passing down the ultimate technique, "Amakakeru Ryuu no Hirameki" of Hiten Mitsurugi-ryu.