I didn't knowit before coming, but Ryougoku is famous for holding Sumo wrestling matches.
It appeared there was a match on today.
I entered the museum and checked out the exhibitions while talking to a guide then continued alone.
There was a model of Mitsuiechigoya, the original version of what is now Mikoshi department store which I saw the other day.
In the Edo period, it wasn't a department store but sold clothing.
There were various other models of buildings, Japan's old cars and household electronics as well as a recreation of a pre-war Japanese household.
On the train back I was standing next to 2 of the Rikishi (Sumo Wrestlers).