Many Japanese consider Buddhism as being synonymous with Buddhism. Many say there were “born Buddhists”. However, it seems though roughly 32% consider themselves Buddhist, the other 52% consider themselves non-religious or Folk-Shinto.
Buddhism arrived in Japan in 520-550 from India via China.
Of the three schools of Buddhism, Mahayana spread to Japan the most.
Of the 127 million Japanese, some data sources record only 8 million (7%) being Buddhist. Whereas other datasources have it at 45 million (35%)
The spread of Buddhism in Japan is inconsistent.
As with the christian church, different schools of Buddhism have “laid claim” to different regions of Japan.
The other interesting thing about Japan is that many Japanese will tell you that they are both Shinto and Buddhist. Many joke you are born Buddhist and die Shinto, based on the type of ceremonies held for births and deaths. As you can see from the below chart, the percentage of Shinto followers coincides with the percentage of Buddhist followers in most areas.