Sword of the Stranger is a Japanese animated feature film directed by Masahiro Andō and produced by BONES studios. The film follows a swordsman with no name and a golden-haired assassin as circumstances draw them towards a mysterious young boy.
That's the central plot but here's what you really want to know:
BONES ☑ Music by the man who's worked on Eureka 7 and Heroic Age ☑ Samurais during the sengoku era ☑ Crazy battle hungry Gaijin working for the Chinese Imperial Army ☑ Gore and violence ☑ Awesome fight scenes ☑