Something that no one seems to mention in their analyses of this shot is the choice of vase. This is not a Japanese style vase. It is a Chinese-style fengweizun (鳳尾尊) vase. Since Ozu also included a Japanese tea ceremony at the beginning of the film (an event which seen by many as the pinnacle of traditional Japanese culture and aesthetics) I have a feeling that he has a strong sense about ceramics and traditional art. If Ozu wanted a truly "Japanese" image, he could have used a large earthenware jar like those used in Tea ceremony. Instead, he's chosen a very Chinese looking vase. The best interpretation i can get with this is that Japanese culture inherited a lot of it's societal and gender roles from Chinese confucianism. So looking on the rigid and strong shape of the chinese vase is a reminder of the long history of established societal roles in Japan that were adopted from china. The connection to china could be a bit of a stretch, but this is a very overlooked detail about the vase.