The two religious groups with the most followers in Japan are Shinto and Buddhism. Although Shinto has slightly more followers, both religions are counted as having nearly the same number of adherents, which actually amounts to roughly double the population of Japan. The reason for this phenomenon lies in the nature of Shinto, which is a polytheistic belief system. Because Shinto can incorporate any deity into its pantheon, people can be followers of both Shinto shrines and Buddhist temples simultaneously, as they are not mutually exclusive.

If you were to ask a Japanese person what religion is, the majority would likely answer that they are "atheists," unless they practice a specific religion. This is because the concept of "religion" in Japanese has become a more generalized term with modernization, which is somewhat disconnected from the original customs and beliefs. 

When people speak of "practicing religion," the image often conjured is that of choosing and adhering to a specific belief system, such as studying the Bible and attending church on Sundays. However, Shinto has no dogma, and there are no weekly gatherings. Rather, Japanese people's faith may be more closely related to a sense of awe toward something great. It might also be more about participation in rites of passage. For example, when a child is born, parents visit a shrine for the "omiyamairi" (a traditional first shrine visit), and whenever they have wishes, they visit shrines or temples. Funerals are typically conducted in the Buddhist tradition. In this way, faith is closely tied to significant moments in life.