Damien Thomas could not speak any Japanese when he was cast. The whole crew were astonished by his nearly-perfect Japanese-language scenes.
Will Adams, the real-life English sea captain and adventurer who made it to Japan in the 16th century, has a street named after him in Japan: Anjin-Cho.
Nagashima, the filming location for Anjiro, was so remote it was hard to find accommodations for the whole crew. Due to a misunderstanding, the crew lost their bookings on September 1st, not the 15th as planned. Changes had to happen to finish by September 1st, but they managed to do it. On the day filming ended, a typhoon destroyed the set.
When Toshirô Mifune was wearing his Lord Yoshi 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.
James Clavell based the character of John Blackthorne on Will Adams, a real-life English sea Captain and adventurer, whose experiences in late sixteenth century Japan are paralleled by Clavell's story.