When Komaki (Toshirô Mifune) is telling Lady Ochii of the recent events at the end of the film, he mentions that on April 13th Miyamoto Musashi defeated Kojiro Sasaki in a duel. Mifune actually played Musashi in 4 different films: Kanketsu Sasaki Kojiro - Ganryu-to Ketto, Miyamoto Musashi, Zoku Miyamoto Musashi: Ichijôji no kettô and Miyamoto Musashi kanketsuhen: kettô Ganryûjima (the last 3 movies comprising the Samurai trilogy, also directed by Inagaki).
The film's original Japanese title translates to "Life of a Swordsman".
When the Battle of Sekigahara is shown, footage is used from director Hiroshi Inagaki's film Miyamoto Musashi (1954), which also starred Mifune.