Maboroshijō dainiwa shi no senpū (1940)

The undercover agent Tsukinosuke Kigurumi successfully escapes with Kirisaku, who possesses the coveted Shinshu Mountain map targeted by the phantom gang, but loses the key to unlocking it. The one who picks up the key is Osumi, a female courier. (Existing version. Please excuse any deterioration in image quality due to original conditions.)