In order to achieve maximum authenticity, actors were fed very little, and were not permitted to tend to matters of simple hygiene such as brushing their teeth and cutting their nails. As a precaution against serious deterioration of the actors' health, a number of nurses were always on call on the set.
Eiji Funakoshi was never specifically told not to eat. He willingly starved himself to help get him into character. The rest of the cast and crew were unaware of this until he collapsed on-set. Production was shut down for two weeks.
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