I like Tokyo in the early morning, deep late night or midafternoon in hot summer. In those hours Tokyo is less crowded and going slow & quiet. But when it comes to the most quite Tokyo, it would be in New Year and Bon holidays. A lot of people get out of Tokyo, going home to see their family for those traditional holiday seasons and Tokyo falls into a hush. Especially, during New Year.
Last weekend we went out for walk to enjoy the silence still remaining in the air.