Traveling in Japan

Hi,

I am planning on traveling in Japan between March 23rd to March 31st, both arriving and leaving from Narita airport in the late afternoon. My initial Itinerary as follow:

23rd and 24th in Tokyo
25th in Kyoto
26th in Kobe, spending the night at Arima Onsen
27th half a day in Arima then head to Osaka
28th in Osaka
29th in Tokyo and Yokohama
30th day trip to Nikko
31st half a day in Shinjuku, then go to airport.

My question is should I leave Osaka on the 28th evening or 29th morning to go back to Tokyo?
Thank you for your help!!