Ran (1985)

Japanese warlord Hidetori Ichimonji decides the time has come to retire and divide his fiefdom among his three sons. His eldest and middle sons - Taro and Jiro - agree with his decision and promise to support him for his remaining days. The youngest son Saburo disagrees with all of them arguing that there is little likelihood the three brothers will remain united. Insulted by his son's brashness, the warlord banishes Saburo. As the warlord begins his retirement, he quickly realizes that his two eldest sons selfish and have no intention of keeping their promises. It leads to war and only banished Saburo can possibly save him.—garykmcd