Halloween is so much bigger now in Japan than I have ever seen it. When I was first here in the 90s no one had really even heard of Halloween and now it is all over the place. I guess people have seen the marketing advantages it has. Anyway, so there were pumpkins all over the place, Halloween treats and even a Halloween themed section of the 100 yen store. In fact it was at a 100 yen store where we got our costumes- witch, pumpkin and old man.
On the Saturday before, we went to the local shopping street where they had a trick or treat activity. We went to a community center where we received a post card with a picture, every store had a picture posted outside, if the pictures matched we could get a treat from that store. It was a lot of fun. Some stores that we frequent gave us treats even if our pictures didn't match. Afterward we went to the community center to make some Halloween crafts.
On actual Halloween some neighbor kids came over for some American candy. It was raining and pretty miserable, but they came anyway- along with their parents. They all said it was fun and we had fun doing it too. Later on a Japanese language blog I saw pictures of Japanese kids trick or treating in their neighborhoods, so maybe its catching on.