Japanese religion is a general term used to describe the unique combination of a great variety of religious traditions within japan religion in japan reflects a long history during which various religious beliefs and practices—some indigenous, some imported from other places—have been adopted and adapted to japanese culture.
Early history and culture one of the most recognizable remnants of japan's so-called tomb period is the tomb of emperor nintoku, who is said to have reigned during the 4th century with all the technological innovations coming from modern japan, it's easy to forget that even they had a stone age.
Religion in japan is dominated by shinto (the ethnic religion of the japanese people) and by buddhism according to surveys carried out in 2006  and 2008,  less than 40% of the population of japan identifies with an organized religion : around 35% are buddhists , 3% to 4% are members of shinto sects and derived religions , and from fewer than 1%    to 23% are christians. The earliest people in japan probably brought with them ancient religious ideas from africa they used red ochre to bury dead people, for example by the time japanese writers wrote books describing their religion in the 700s ad (the kojiki and nihon shoki), these early ideas had developed into shintoism.
Shinto was already well established as the national religion when buddhism was transmitted from china (via korea) to japan in the 6th century ce as buddhism gained popularity, it occasionally clashed with shinto, but it did not displace the pre-existing religion. In ancient times, the japanese believed that all natural phenomena, animals, and plants possesed kami, or divine power this belief came to be known as shinto and was established as an official religion after buddhism and confucianism were introduced to japan from the asian continent buddhism came. Shinto is an ancient japanese religion starting about 500 bce (or earlier) it was originally an amorphous mix of nature worship, fertility cults, divination techniques, hero worship, and shamanism.
Shinto (the way of the kami) is the name of the formal state religion of japan that was first used in the 6th century ce, although the roots of the religion go back to at least the 6th century.