We found this place by accident taking a stroll from Mejiro to Ikebukuro to burn off lunch.
Mejiro Tei-En is a garden run by the government of Toshima-ku, a part of metropolitan Tokyo. The garden is free (we checked on the local government web site - we visited on a national holiday but it's free every day).
The path around the outside reveals nice views across a carp-and-goldfish pond and is surprisingly quite and green in concrete Tokyo. Near the entrance and exit there are benches or a gazebo to sit and pass the time, climate permitting, in the company of some koi carp. It'd be great for a little garden photography and relaxation, and mostly there aren't any tall buildings nearby to intrude into the shots too much.
Only snag: you might need GPS to find it.
Our host from Family Inn Saiko recommended us this little garden because it is light with colourfull lights at night. We went there and it was really interesting, there were only a few other people, entrance fee was small. Wery good place for night stroll, great for night photography and cool/unique experience.
