Rogue (1968)

Coal miner Isamu Oba is forced to quit his village and leave his mother and siblings behind. Mining buddy Ichiro accompanies him to Tokyo, and the pair enjoy several "fish-out-of-water" sequences before finding employment at a boxing gym with trainer Sawada and his spunky sister Tomoko. The boys also find part time night jobs as roving minstrels in the club district courtesy of benevolent gang boss Asakawa. Of course, they run afoul of boss Karasawa's cruel gang. Karasawa also has it in for Asakawa, and this indirectly throws a spanner into the works as far as Isamu's burgeoning success as a kickboxer. When Asakawa's HQ is burned to the ground by Karasawa's men, Asakawa tries to kill Karasawa - which, of course, leads to his own gruesome death. Isamu goes on the rampage with his sword, wiping out Karasawa and men.