Complex sentence: He first arrived on the island of Japan in December 1974, and his first exposure to film and acting was in 1978 as an extra (U.S. Marine Sentry) in the "The Bushido Blade" starring Richard Boone and Toshiro Mifune.
Split into simpler sentences: He first arrived on the island of Japan in December 1974. His first exposure to movies and acting was in 1978 as an extra (U.S. Marine Sentry) in the "The Bushido Blade" starring Richard Boone and Toshiro Mifune.