In the late summer, I discovered the Japanese garden Rikugi-en located in the neighborhood of Sugamo. Tokyo also has authentic and quiet places, this garden is one them. At the center: a pond, an island with Japanese pine trees (matsu), a bridge and a tea house. I took me at least an hour to explore the garden, to take the different slopes around the lake, along the river and on top of the hill. From here, you can enjoy a panorama of the garden, and the contrast with the buildings of Tokyo is nice.
From mid November to mid December, you can enjoy evening illuminations until 9pm. Fall colors are a must see, and with proper lightning, the atmosphere takes on another dimension. Rikugi-en is one of the few places in Tokyo where you can enjoy Momiji (when maple leaves turn red). Too bad I missed it last year !
Open everyday from 9:00 to 17:00
Entrance fee is 300 yen
Closest station is Sugamo on the Yamanote Line (15min from Shinjuku)