Shinbutsu-shūgō (神仏習合 literally "syncretism of kami and Buddhas"?), also called Shinbutsu-konkō (神仏混淆 literally jumbling up or contamination of kami and Buddhas?), is the syncretism of Buddhism and kami worship that was Japan's only organized religion up until the Meiji period. Beginning in 1868, the new Meiji government approved a series of laws that separated Japanese native kami worship, on one side, from Buddhism which had assimilated it, on the other.
When Buddhism was introduced through China in the Asuka period (6th century), rather than discarding the old belief system, the Japanese tried to reconcile the two, assuming both were true. As a consequence, Buddhist temples (寺, tera) were attached to local Shinto shrines (神社, jinja) and vice versa and devoted to both kami and Buddhas. The local religion and foreign Buddhism never quite fused, but remained however inextricably linked all the way to the present day, always interacting. The depth of the resulting influence of Buddhism on local religious beliefs can be seen for example in the fact that much of Shinto's conceptual vocabulary and even the types of Shinto shrines we see today, with a large worship hall and religious images, are themselves of Buddhist origin. The formal separation of Buddhism from Shinto took place only as recently as the end of the 19th century, and in many ways the blending of the two still continues.