Tokyo, right after the war. A young man brings Kohei, a boy of maybe 8 years old, to the young man's home. Kohei was wandering around lost, having gotten separated from his father in the suburb of Chigasaki. The young man's father Tone categorically refuses to host a child, and the boy is eventually foisted onto his neighbor Tane, a widow.
Tane is not at all happy about this. First she tries to shoo Kohei out of her little house. Later, after they go to Chigasaki but fail to find Kohei's father, Tane tries to abandon the boy at the beach. But Kohei sticks by Tane, and eventually they bond.
- "Blind Idiot" Translation: The English title, which was rendered literally from the Japanese. Wikipedia reports that a better title would be "Who's Who of the Backstreets".
- Child Hater: Nobody wants to look after the lost boy; Tamkichi straight-up says "I don't like kids."
- Children Are Innocent: Towards the end Tane muses about how kids in post-war Japan are busy struggling to avoid starvation when they should be happy and carefree.
- Defrosting Ice Queen: A non-romantic example. Tone is initially very put out when Kohei gets foisted on her. She tries to ditch the boy in Chigasaki. She chastises him for wetting the bed, harshly scolds him again for eating the persimmons (which as it turns out he didn't even do), and is generally harsh and unfriendly towards Kohei. But eventually the frosty facade melts and by the end she's asking if he wants to be her son.
- Heartwarming Orphan: Not technically an orphan, as his father's out there somewhere, but the trope still applies to sweet little Kohei.
- Japanese Politeness: Discussed Trope. Tane berates herself for not being nicer to Kohei, then starts ruminating about how the traumas and deprivations of the war have eroded Japanese Politeness."Even when we get on a train we shove people aside. We don't care if other people starve as long as we get our fill."
- Missing Mom: Most likely killed in an American bombing raid.
- My God, What Have I Done?: Tane is horrified when her harsh scolding about Kohei wetting the bed results in him running away when he does it again.
- Scenery Gorn: Bombed-out buildings and piles of rubble in the hardscrabble neighborhood where Tane lives.
- Signature Shot: The shot-reverse shots of two people carrying on a conversation, centered in the frame, which Ozu did throughout his career.
- Slice of Life: Lower-class people struggling to survive in Tokyo in the aftermath of the war.