When Toshiro Mifune was wearing his Toranaga samurai gear he went completely into character, grunting and growling constantly and always with an angry look. Nobody dared to go close to him in such moments.
Nagashima, the filming location for Anjiro, was so remote it was difficult to find accommodations for the whole crew. Due to a misunderstanding, the crew lost their bookings on the 1st of September, and not the 15th as planned. Changes had to be done in order to be able to finish by September 1, but they managed to do it. On the day the shooting ended, a typhoon destroyed the whole set of Anjiro.
In a Japanese TV interview made around the time of the filming, Toshirô Mifune stated that the original script had his character speaking modern Japanese, and that he corrected the anachronisms in the language to forms that were more appropriate to Japanese as it was spoken in the 16th century.
Just one week before production, the Japanese actress chosen for the role of Mariko left the project--she was a singer and had to go on tour. This was a major headache for the team. Still, production was not stopped and a whole month was shot before Yôko Shimada was hired to play Mariko.
The set for the village of Anjiro was built in Nagashima, a remote virgin beach in a fishing village. It was so remote that there was no road leading to it, so it had to be built. The trees removed to do so had to be replaced after production finished.
Luca Bercovici, son of scriptwriter Eric Bercovici, was hired as dialogue coach for Yôko Shimada. There were some words she was not able to pronounce, so they were changed to tailor the script for her.
The ship used for the Erasmus was called The Golden Hinde. It was hired in London and sailed to Yokohama via San Francisco. This is the same ship used for the Black Ship, so it had to be modified to look different.
English actors were hired for the entire six months that production was going to take. It was not possible to do the same with the Japanese actors, especially Toshiro Mifune, so during filming there was a constant negotiation about his availability when necessary to meet the shooting schedule. Apparently at some points negotiations became very tight and tense.
There was a previous attempt to film the story of Will Adams , on whom James Clavell based his story. Peter O'toole and his producing partner Jules Buck had tried to set it up in the mid 60's, and both Fred Zinnemann and John Huston had both been attached to direct. Toshiro Mifune was also set to star.