Here's the interactive map.[1] Most of those charging stations are not public. Hotels and auto dealerships have some of them. I've been looking for them in Google Maps. Here's one that's in a public parking lot and has signage.[2] You have to pay for parking to charge, but that's not unreasonable in Tokyo.

[1] http://www.chademo.com/wp/jpmap/ [2] https://goo.gl/maps/M5WYLuM4uEK2