Temples and Shrines

People in Japan have practiced both Shintoism and Buddhism for a long time; one religion is not exclusive of the other. Shinto is the indigenous religions and Buddhism originated in mainland east Asia. The most common sort of Buddhism you're likely to see in Japan is Amidst or Nichiren. Shinto is pretty much Shinto, a religion based on animism. Because both of these religions are important you can find shrines and temples all over from small to large, unknown to world heritage sites. Buddhist temples are generally denoted by the -ji on the end of the name and Shinto shrines are called jinja.

If you look at a map of any major Japanese city it will be dotted with shrines and temples. For example, pull up Tokyo in Google maps and scroll in. You will see Tori (shinto gates) representing Shinto shrines and Buddhist swastikas, representing temples. If you want to see a lot, in close proximity, try Kyoto or Kamakura.

One example is Senso-ji, a Buddhist temple in the neighborhood where we'll be staying in Taito, Tokyo. It's know for the Kaminarimon gates and its long history, which goes back to 628. It is the oldest temple in Tokyo. Close to Senso-ji is a shinto shrine, Asakusa-jinja, honoring the people who founded Senso-ji and showing how connected the two religions are.

Senso-ji is dedicated to Kannon.

Japan Guide has a small entry on how to behave at Shrines and Temples here.