I found a couple of Halloween events in the Tokyo area.
There is the annual Roppongi Hills Halloween Parade on Saturday October 27, from 11:00- 13:30. In the area, the Stomp Stamp store is giving candy to kids in costume. Tokyo City View is also giving candy to kids in costume who shout “trick or treat!” and they can get free admission to the observatory deck.
In Kanagawa there is the Kawasaki Halloween Events, at La Cittadella which includes a children’s parade on Saturday October 27, at 11:00, 13:00 and 15:00. Info is in Japanese only so I don’t know the specifics.
I’m sure there are more so if anyone knows of any others, please let me know.
My Friend Nora just sent me a link to another Halloween parade which looks like a lot of fun.
It’s today in Harajuku, along Omotesando. Check http://www.harajuku-halloween.com/ for info (only in Japanese though)