Eli Wallach's fourth Spaghetti Western, and his seventh and final Western film.
The colors of the chest's three locks correspond to the movie's original title "The white, the yellow and the black".
The character of Sakura inspired the similar protagonist of Delitto al ristorante cinese (1981), still acted by Tomas Milian but directed by the brother of Sergio Corbucci, Bruno Corbucci.
When the trio makes camp for the night the Swiss is asking Sheriff Gideon to respect the rules of the Geneva Convention and feed him supper(0:43:26).The Swiss is referring to the First Geneva Convention for the Amelioration of the Condition of the Wounded and Sick in Armed Forces in the Field of 1864.
In the opening scene of film, Sheriff Edward Gideon (Eli Wallach) has an argument with her wife (María Isbert) and all the dialogue are phrases that include many western movies titles.