Red Sun

Link (Charles Bronson), a rough-riding gunslinger, teams up with Kuroda (Toshiro Mifune), an honorable samurai warrior, in a grisly tale of revenge set in the lawless southwest of the 1870s.
A gruesome train robbery involving a priceless samurai sword throws the two bitter enemies together. As victims of the same desperado, they are forced to unite to capture the killer and restore the sword to its rightful owner. They have one week to complete their mission or the warrior must commit hara-kiri! The action heats up when they kidnap the killer's beautiful girlfriend (Ursula Andress), a prostitute working in a seedy bordello. Link and Kuroda are determined to get their man...and nothing can stop them! (official distributor synopsis)