Onimasa: A Japanese Godfather (1985) on Netflix

Matsue is the adoptive daughter of the Kiryuin House, a small yakuza clan in Shikoku. Onimasa, their leader, is the last heir to a family of samurai. He is hard in business but respected by the poor because of his fairness. Matsue lives in the middle of this society, between gang wars and rivalries among the chief's mistresses. But when Onimasa takes a chivalrous attitude and finds himself on the side of train workers on strike, it annoys the Great Godfather of the island. The story starts in 1918, ends with the nearing of the Second World War.