My friend noticed how Mariko and Buntaro has to crawl or kneel to get inside the tea room and wonder why the entrance was so small.
If I am not mistaken, Japanese tea houses/rooms have intentionally small entrances, no more than 2 feet by 2 feet, forcing guests to crouch and kneel to enter (which was the way Mariko and Bunataro enterd the tea house). Supposedly, it was designed that way so that people of different ranks and hierarchy can become relative equals inside the tea house, which is meant as a separate world away from everyday life. The idea being that, if everyone, regardless of their social status, enters the tea room the same way, a sort of nominal equality is established inside the tea house.
Btw, Buntaro is based on the real-life samurai Hosokawa Tadaoki, just as Mariko was based on Tadaoki's wife, Hosokawa Gracia, who in real life was also a Catholic. Whether Hosokawa Tadaoki was also an abusive husband as Buntaro was, I am not sure. But the real life Hosokawa Tadaoki was known to be an expert in the tea ceremony, being a disciple of the tea master Sen no Rikyū (who tragically was ordered to commit seppuku by the taiko Toyotomi Hideyoshi over some supposed offence he committed.) So in that aspect of tea ceremony, Buntaro was historically accurate to his real-life counter-part.