Battōjutsu (抜刀術 battō-jutsu: "the craft of drawing out the sword")is a field of kenjutsu (剣術, Literally meaning: Sword Technique) which deals specifically with the rapid drawing and sheathing of a sword. It is the predecessor of the art of Iaido (居合道 a Japanese martial art that emphasizes being aware and capable of quickly drawing the sword and responding to a sudden attack); in that their differences stem from the fact that Iaido is much like Kendo as a form of spiritual training and sport, where Battojutsu practices and studies the dynamics of sword drawing and hand eye coordination regarding live action factors of timing, distance, targeting, and the specifics of one's sword, including its size and blade, to strike readily. It is hence practiced with live swords, in contrast to kata and sparring needs eventually developing the safer bokken and shinai.
In most cases, a katana being drawn from its sheath moves with a much greater speed and force than when it is being wielded normally. Additionally, greater drawing speed gives a swordsman more of an advantage in combat than an opponent whose speed is inferior. This is due in part to the fact that a katana's sharp blade curves upward against the inside of the sheath, allowing the swordsman to use more strength in drawing it without having to worry about applying extra control to his movements - the sword's path is guided by the sheath while the blade meets no resistance, moving two to three times faster than normal. Himura Kenshin is known as the Battōsai ("Unsheather") due to his complete mastery with battōjutsu and can even manage to use his godspeed battōjutsu with a sakabatō with its dull edge curving up against the inside of the sheath as well as use the same godspeed for Nōtōjutsu (the art of sheathing).