Conversation so far:
What film work did Ryuichi Sakamoto do?
Merry Christmas, Mr. Lawrence marked Ryuichi Sakamoto's debut as both an actor and a film-score composer.
Did Ryuichi Sakamoto release any albums?
Ryuichi Sakamoto concurrently pursued a solo career, releasing the experimental electronic fusion album Thousand Knives in 1978. Two years later, he released the album B-2 Unit.

Question: How did his career begin?
Self-contained rewrite: How did Ryuichi Sakamoto's career begin?