Fireworks in Tokyo area:

Sat. 3 Aug. 19:15 - 20:30 Edogawa Fireworks, Edogawa-river banks near Shinozaki station (Toei-Shinjuku subway line) -- my personal recommend, one of biggest fireworks festivals in Kanto area but expect huge crowd.

Sat. 10 Aug. 18:50 - 20:10 Tokyo Bay Fireworks, Harumi-pier Park -- you can see from a lot of places in Bay area.