Akira Kurosawa's eyesight had deteriorated almost completely by the time principal photography began. He could only frame shots with the help of assistants, who used his storyboard paintings as guidelines.
Akira Kurosawa referred to his previous film, Kagemusha (1980), as a "dress rehearsal" for this film. He spent ten years storyboarding every shot in the film as paintings. The resulting collection of images was published with the screenplay.
The film used approximately 1400 extras and 200 horses. 1400 suits of armor (designed by Akira Kurosawa himself) were fabricated and a number of the horses had to be imported from the United States. Kurosawa used the extras and horses so efficiently that when the film was ready for premiere, newspapers in Japan were reporting that thousands of extras and horses were used to stage the battles.
The castle destroyed in the middle of the movie was specially constructed on the slopes of Mount Fuji for the film and then burned down. No miniatures were used for that segment, although an optical of another castle being burned at the end was used.
Unlike most other characters in the film, the character of the fool, Kyoami (Pîtâ), has no basis in historic Japan. The most similar position in relation to a historic Japanese warlord would be a page, but would be quite different in responsibilities. Rather Kyoami is based on the fool or jester of European medieval times and, of course, William Shakespeare's character of the Fool from "King Lear".
Criterion was set to release the film on Blu-Ray in Region 1 territories which would have made this the first Akira Kurosawa film released on Blu-Ray in America. But Criterion lost the rights to the film at the last minute and was unable to release it and all of their earlier releases of the film on DVD were out of print. As a result, Criterion's release of Kagemusha (1980) became the first Kurosawa film released in the USA. However, Ran has since been released in America as a part of the Studio Canal Collection, distributed by Lionsgate.