Diary of a Mad Old Man (1962)

Utsugi, a seventy-seven-year-old man of refined tastes who is recovering from a stroke, discovers that, while his body is decaying, his libido still rages on -- unwittingly sparked by the gentle, kindly attentions of his daughter-in-law Satsuko, a chic, flashy dancer with a shady past. Pitiful and ridiculous as he is, Utsugi is without a trace of self-pity, and his diary shines with self-effacing good humor.