In Ozu's 1957 film Tokyo Twilight, the main characters randomly put on cloth masks.

Judged against the film itself. True: in Ozu's Tokyo Twilight (1957), main characters are shown wearing cloth face masks in one or more scenes, without a plot reason that makes the masks central. Mostly true: masks appear on main characters, but the year or a minor detail is slightly off, for example only one main character wears one. Mostly false: masks appear only on minor or background characters. False: no characters wear cloth masks in the film.

Set before the research began.

1. E1 Tender Restraint: Tokyo Twilight (Yasujirō Ozu, 1957) Senses of Cinema (CTEQ Annotations on Film, Issue 90) · 28 March 2019

   “This view of the city is one in which the characters wear face masks as protection from its contamination, men are arrested for stealing women’s underwear and anti-prostitution laws are enacted.”

2. E2 Tokyo Twilight – 1957 Ozu The Cinema Archives · 25 May 2018

   “we even have many characters with surgical masks (I’m guessing from the possible nuclear fallout but no idea really)—first time in ozu’s oeuvre for that”

Two independent sources confirm that characters in Tokyo Twilight (1957) wear face masks. E1 says 'the characters wear face masks as protection from [the city's] contamination', and E2 reports 'many characters with surgical masks' and says the reason is unclear. Neither source suggests the masks are central to the plot. However, neither names which characters wear them, so the evidence does not explicitly show that the main characters do, and E2 calls them surgical rather than cloth masks.