Tokyo City maps....
Once you are in Tokyo, there are area maps posted on signs throughout the city.... in the subway stations and ground level when you exit the subway.
For something you can carry around with you, I might suggest you go into one of the larger better hotels (act like you belong there), go to the bell captain, and request a city map. We were staying in the Hilton Tokyo and that is where we got our maps. Maybe all hotels carry these maps for tourists.
If you want something before you leave for your trip perhaps this may help. The e-mail address printed on the map that I have is
info@hatobusagency.co.jp
What I have is Map of Tokyo, Vol 39 No. 4 156.
I am guessing that someone there might read/speak english.
Christine