When I came to Japan back in 1991, I had a lot of pre-conceived notions about the place, many of which proved wrong. One of these was the idea that the Japanese were "not religious," so imagine my surprise at finding myself in the Maebashi Baptist Church my first Sunday after arriving, where I'd been invited by some of my students. The next week, I even ran into some Jehova's Witnesses standing in front of the station, handing out Japanese-language versions of the Watchtower. Now my daughter attends a Christian school established in 1888 by missionaries who'd come to Japan during the Meiji Era, which makes for some interesting discussions when it's time for me to help her with her homework. One challenge is that since the Japanese version of the Bible was translated from the original ancient texts rather than from the English version, all the names sound very strange to my year, like Paulo, Petro and Yohan for Paul, Peter and John. If you want a linguistic challenge, try reading the Old Testament in Japanese! (If you're curious, between 1-2% of Japanese report themselves as Christian.)
I've known quite a lot of Japanese Christians during my time here.