The popular conception of chambara as "Samurai Film" is justifiable. Apart from the Ninja and Yakuza sub-genres of chambara, the solitary figure of the samurai remains as the foundation upon which the classic Japanese action film was based.
The primary genre expectation of any chambara film is the swordsman. Whether this character is later developed as a hero or anti-hero, the protagonist's physical introduction into the scene, usually in the film's first few minutes, the viewer is forced to recognize him as the potential dramatic center of the plot. This basic character convention is the key narrative element in all samurai film. The samurai, the ninja, the fighter, the gangster, and especially, the ronin, all share the same defining characteristic -- they must be armed either literally or figuratively. In the case of classic chambara, the sword serves as the genre's de-facto icon. A weapon and a tool, it projects and personifies the spirit of the warrior. In the case of the "fighter" sub-genre, the sword is at times taken figuratively to represent the fighting spirit or fervor of the warrior. The representation is internalized, transforming the sword into something less obvious but just as deadly -- the fist. A similar transformation is occurs in the yakuza sub-genre, where skill with the gun replaces skill with the sword.