Dagger of Kamui (1985) aka Forrest Gump w/Ninja. Directed by Rintaro, our lord and savior, hallowed be thy name.
Follows this kid by the name of Jiro, who continually has friends and family drop dead around him due to the Shogunate fucking with him non-stop. There are so many plot & character twists, you'd swear a few of them almost developed dimension. We're talking ninja clans, supernatural assassins, double-crosses galore, and Ainu in the first hour.
The second hour is where it all goes purely batshit, and becomes a classic. The story continues on to develop multiple master/slave relationships, a travel across the Pacific, landing in Nevada before California, near Indian rape, a high noon shootout, Captain Kidd's secret gold treasure trove, and then a trip back to Japan as the Shogunate falls and revenge is served with cannonballs. Mark Twain appears for a heart to heart with Jiro, and Saigou Takamori (The Last Fucking Samurai) pops up at the end. Hell, Jiro was voiced by Hiroyuki Sanada, who played Ujio in The Last Fucking Samurai.
It's too long due to a relentless barrage of flashbacks throughout, and seems opposed to the usage of sound as if it was heresy. The passage of time is handled expertly, so much so that an innate desire to find a save point occurs from scene to scene. This sucker deals with more locations and oddball characters than a Hironobu Sakaguchi production.