Red Sun is an international movie. The four main actors are: Charles Bronson from the US, Toshiro Mifune from Japan, Alain Delon from France, and Ursulla Andress from Switzerland. The director Terence Young, who is perhaps more well known with his work James Bond's Dr No, is British. The movie is shot in Spain. The setting is in America's Wild West.
As can be guessed from the title, it has something to do with Japan. Japan's national flag is Hinomaru, which shows a red circle (=the sun). In 1870, Lord of Bizen, the Japanese Ambassador, is traveling through Wild West by train when Link (Bronson) and Gauche (Delon) rob the gold shipment, despite the fact that the train is guarded by cavalry. Gauche, who also takes a gold sword, a present for the US president from the Japanese government, tries to murder Link, but fails. Lord of Bizen asks Link to lead his Samurai (Mifune) to find Gauche and retrieve the sword in 7 days, or the Samurai should do harakiri. Link wants Gauche to live long enough to show him where the gold has been hidden, while the insulted Samurai must kill Gauche at the first sight. To provoke Gauche, so he comes out from his hiding place, Link kidnaps Cristina (Andress), Gauche's mistress.
This movie has wonderful cinematography and the dialogues are funny at times. I like the soundtrack by Maurice Jarre. I didn't notice it at first, but when I listened to the music only, yes, it was lovely. I also like the rhythmic sound inside the train, which I think is similar to sound in the scene when they are being attacked by the Comanches. The movie is mostly about the friendship which slowly grows between Link and the Samurai.
Alain Delon's gold tooth makes him more annoying. The only kind thing he does in this is when he protects Cristina from the smoke with his jacket. It's a typical Frenchman, I think. Link or the Samurai will never do anything like that. Delon's character's name, Gauche, means 'left' because he's a card player well known with his left hand's skill. There is a wonderful scene where he jumps from the roof.