Today it may be hard to understand the classed societies that prevailed pretty much everywhere before the 1800s and how slowly they changed to more egalitarian ones. Japan was a very class conscious society even up to WW II. There was a lot of imitation of the West but the attitudes towards the nobility changed very slowly. There were no peasants in the original stories Seven Samurai and the Samurai Trilogy were based on, but peasant heroes of noble character were portrayed in their movies to make a point about human equality.
Both of those stories were retold from many older versions, Samurai trilogy was based on the real life of Miyamoto Musashi who was actually the son of a head of a fencing school, and not a peasant at all as he is portrayed in the movie. Seven Samurai was also retelling, though probably about how Samurai who had fallen on hard times retained their noble character. Even a very promising fighter would not have gotten a pass to join the group with a stolen birth record, certainly not one that indicated he was 7 years old! Having to resort to working for peasants was lowering enough. Portraying the revelation of Mifune Toshiro's character's character and abilities, his equality with his new comrades and their gradual acceptance of him, makes the point.
In Rickshaw Man we have a much more direct message piece: a man of noble character whose position is way at the bottom of even the peasant class! I remember seeing this movie in the 1960s and it seemed obvious to me that it was set in the 1940s. The lady's officer husband (officers were Samurai class) went off to war and was killed. This was a common occurrence at several points between 1880 and 1945 and this makes her a very sympathetic character. She is also of course Samurai class. This gulf between their classes would have been unthinkable to cross for people who had grown up before 1940. S, more so for any of the possible prior years. Stepping between rich middle class and modest Samurai class may have been happening but was still a big deal. Notice that by showing the Lady's husband as being generous and thoughtful in desiring to reward the rickshaw man for his help he is carefully preserved as noble also; there is no making the upper classes villains here, just showing that others are virtuous also.
In 1959 when the heir to the Emperor married a commoner, the daughter of the head of Nissan Flour Milling Ltd, it was a very big deal indeed! Much was made about how her upbringing had been the equal of a Samurai daughter, not by directly saying so, but by describing it and her accomplishments in detail. However, this too, was obviously a message. The Emperor wanted attitudes to change.
So in Rickshaw Man we have the title character established not only as lower class than farmers but a trouble maker: as low as he could be without being a criminal or a traitor. Not only is he good-hearted, he has tremendous joy in being alive. He is also virtuous in his respect for people who are supposed to be his betters and noble in not resenting his own status. As Mifune Toshiro portrays him, he is positively inspiring. Clearly, this is a movie intended to change peoples minds and hearts. I can't imagine anyone who saw it leaving the theater without thinking that maybe the lower classes might be okay, at least some of them. Japanese culture was changing and these movies were helping it as much as they could. It was also inspiring news to all those not lucky enough to be born Samurai--which was maybe 90%, so this message would be popular, too.
