Peony Lantern Ghost Story (1968)

Shinzaburo flees an unwanted marriage with his brother's widow and lives quietly as a teacher distanced from his family. On the night of the summer Obon festival, he meets a beautiful courtesan named Otsuyu, whom he doesn't recognize as a ghost. But his interactions with her are leaving him weakened. Because she has a much more obviously ghostly attendant, Shinzaburo becomes frightened & visits Kiku, the temple priest, for an exorcism.