Based on information from Weathernews Inc, here is the latest forecast on the best timing for the autumn colors in the major tourist locations around Tokyo:
Nikko (Chuzenji0ko Lake area): From Oct 23
Nikko (Toshogu Shrine): From Nov 2
Kawaguchiko Lake near Mt Fuji: From Nov 8
Hakone (Lake Ashi) : From Nov 9
Mt Takao: From Nov 12
Central Tokyo (Ginkgo Trees in Aoyama) : From Nov 22
Kamakura (Tsurugaoka Hachiman Shrine): From Nov 28
The peak viewing period last about two weeks.
The Rikugien Garden, one of the best places within Tokyo to watch the foliage, will have extended hours from Nov 19th to Dec 7th. Parts of the garden will be illuminated after dark and remain open until 9pm (last entry 8:30pm)