Stray Dog (野良犬, Nora inu) is a 1949 Japanese crime drama noir film directed and co-written by Akira Kurosawa, starring Toshiro Mifune and Takashi Shimura.

Murakami (Toshiro Mifune), a newly-promoted homicide detective in the Tokyo police, has his Colt pistol stolen while riding on a crowded trolley.

After Nakajima encourages him to conduct an investigation into the theft, the inexperienced Murakami gets a lead from one of the ladies who traveled in the trolley and goes undercover in the city's backstreets for days, trying to infiltrate the illicit arms market.

A rice ration card found on his person reveals that the gun was loaned to Yusa, a disenchanted war veteran who has become involved with the yakuza to support himself.

The detectives interview Yusa's sister, one of his yakuza associates, and his sweetheart, showgirl Harumi Namiki (Keiko Awaji); but none of these visits produce any useful leads.

She is still reluctant to talk, so Satō leaves to trace Yusa's movements, while Murakami remains behind hoping that Namiki's mother can persuade her to begin cooperating.

He tries to call Murakami, but just as he is about to reveal Yusa's location, the criminal (having overheard the hotel owners mention that a cop is present) shoots Satō twice before making his escape.

The following morning, Namiki has a change of heart and informs Murakami that Yusa called and asked her to meet him at a train station so they can skip town.

Murakami races to the station and manages to get a positive identification on Yusa by taking into account his age, white suit stained with mud, and left-handedness, three tips he has collected over the past few days.

He had to write a letter to American occupation officials denying the allegation, and he later said that he never felt "a stronger sense of regret over Japan's losing the war.

Ishirō Honda, who would go on to direct several monster movies such as Godzilla and Mothra, served as Kurosawa's chief assistant, shooting second unit footage for the 10-minute long sequence of Murakami roaming through Tokyo, and often doubled for Toshiro Mifune in waist shots.