The Great Hero Yi Sun Shin(1971)

Original title: 성웅 이순신

A famous general who defeated Japanese invaders with the world's first iron ship, 'Turtle battleship' during Chosun dynasty, was intrigued against by many villainous retainers. Even when he was reduced to a much lower rank, he served in the war worrying about the nation's wellbeing. This film depicts General Lee Sun-Shin who is probably the most famous general in Korean history, based on his 'Wartime Diary.'