Passing Fancy

Yasujirō Ozu regular Chishū Ryū has a small role towards the end of the film as a fellow passenger on board a ship, playing an uncredited "Man on Boat".

Kihachi states that 50 sen to a boy his age (referring to Tomio) is like 10 ryo to him and Otome. The ryo was replaced by the yen in 1871, over 60 years earlier. (The yen replaced the ryo at par; there are 100 sen to the yen.)

However, Otome then says, "No, more like 1,000 yen!" So, it's possible "ryo" was still being used synonymously with "yen" over a half-century later.