Bound for the Fields, the Mountains, and the Seacoast 1986 one on netflix

During the fervently nationalist months leading up to World War II, a rebellious teenager is transferred to a new primary school in a small Inland Sea town. He vies with the school’s reigning bully, who takes a romantic interest in his older stepsister. When they learn she’s going to be sold to a brothel to pay off her father’s debts, they form an uneasy alliance to free her.