Toshiro Mifune was George Lucas's original pick for Obi-Wan Kenobi; his role as Gen. Rokurōta in The Hidden Fortress was the inspiration for Kenobi's character in the first place. Incredibly, before he turned down the role (Mifune worried the sci-fi story would look cheap and make samurai look silly), George Lucas was even toying with shooting the entire film in Japanese.
Recently I was looking into this and found a very interesting quote from Mika Mifune, Toshiro Mifune's daughter.
“I heard from my father that he was offered the role of Obi Wan Kenobi, but he was concerned about how the film would look and that it would cheapen the image of samurai, on which George Lucas had based a lot of the character and fighting style. [...] At the time, sci-fi movies still looked quite cheap as the effects were not advanced and he had a lot of samurai pride. So then, there was talk about him taking the Darth Vader role as his face would be covered, but in the end he turned that down too.”
Interestingly, the remark about sci-fi looking "cheap" as Mika Mifune puts it is almost echoed word-for-word in this 1977 interview with George Lucas (an interview that frankly deserves a post all its own). When asked about when Star Wars would open overseas, he responds with this:
"Science fiction has reached this very crummy level in Japan. They love it but it is still very crummy. It’s been exploited just like they did in [the United States]. The wrong people have been doing science fiction. Science fiction – speculative fiction – is a very important genre that has not been taken very seriously, including the literature."
All due Horny to Ewan Mcgregor but if this MFer showed up in phantom menace people would have been trying to fucking climb into the screen
