The styles of karate used by the characters are all different: Taikan trains Shotokan style. Giryu trains Goju-Ryu style. Choei trains Kyokushinkai style
Originally, Karate was called Totejutsu (Art of the Chinese Hand) by Okinawan master Gichin Funakoshi Sensei when he brought it to mainland Japan in the early 1920s. Because of the extreme Japanese nationalism forcing him to deemphasize the Chinese roots of the art, Funakoshi changed the name from Totejutsu to Karatejutsu (Art of the Empty Hand). The style of Karate he founded was Shotokan, which has roots in Okinawan Shuri-Te (the root of another Okinawan Karate style Shorin Ryu). Shotokan Karate would later be the major part of the basis of the Korean Tang Soo Do; the name is the transliteration of Karate's original name. Shotokan would later be the cornerstone of subsequent Japanese styles such as Wado-Ryu, Chito-Ryu and Kyokushin.