How do you find a place at the other end of the world that you only know from TV?
Well, that's easy: google. In one episode of Kinpachi Sensei I heard Kinpachi mention the Arakawa River. Google for "kinpachi" and "arakawa" and the very first result is what you are looking for: Kinpachi Sensei was filmed on location in Kita Senju, Adachi-ku, Tokyo. But where exactly? If you look at the show, many times you will see two railroad bridges in the background that are very close together. Get a map of Tokyo, find the Arakawa and look for two bridges. It really is that easy.
On the left you can see Kita Senju Station. Two tracks from there go right across the river. There are many other railroad bridges across the Arakawa, but never two of them so close together. So this had to be it.
On the day after the Ya-Ya-yah Concert, two days after the final episode of Kinpachi Sensei, I took the train to Kita Senju and walked from the station to the river. Below you can see some screenshots of the TV series. If you move your mouse over the pictures you will see the corresponding pictures that I took on that beautiful sunday afternoon in March along the Arakawa.