People generally shy away from serious religion here. They call themselves adaptable and pragmatic, cause they celebrate a very secular Christmas (mostly just for kids and couples that have just fallen in love), they go to the
Shinto shrine on the New Years, and they attend funerals and memorial services at Buddhist temples (most of them do anyways, some are also Christian).
Being seriously religious in a lot of Japanese eyes might be repeating the mistakes of their past, such as the Emperor worship during WW II, they also point to the Islamic Jihadists as another reason why religion is not a good idea. A lot feel that religion causes a lot of wars.
You could try asking some religious people in Japan what the best way to reach out to people is, but it would be challenging here to preach whatever religion it is you're preaching.
I heard of a van with some 'be saved or go to hell' slogan on it driving around here. Fortunately the Japanese don't really understand English well enough to know what it says, cause it's a prosyletization method that has turned a lot of people off from Christianity in other countries. These days it's more along the lines of 'I'm living in paradise now cause I've got Jesus in my life'.
I've got a very religious Christian women in my class, and she talks about God and Christianity for her presentations. There is one student there who doesn't mind discussing it a little with her, and another who's just interested in religions of all kinds, but the rest of the class tunes out or mutter to each other something about religion being unnecessary.