The vast majority of Japanese people are followers of Buddhism as well as Shinto. Buddhism originated in India with a wealthy Hindu prince called Siddhartha Gautama who, dissatisfied with Hinduism's explanation of worldly suffering, rejected asceticism as the way to spiritual realization and turned instead to meditation. After several nomadic years he achieved enlightenment ( nirvana ) while meditating one night under a bodhi tree, and devoted the rest of his life to teaching that "right thoughts" and "right actions" must be followed to reduce all material and emotional attachments in order to increase awareness and ultimately to attain nirvana .

The Mahayana (Greater Vehicle) school of Buddhism, which believes in salvation for all beings jointly rather than the individual pursuit of nirvana , was introduced to Japan from China in the mid-sixth century. As with many things, Japan adapted this foreign import to suit its own culture and values. Buddha was accepted as a kami and, over the years, certain religious aspects were dropped or played down, for example celibacy and the emphasis on private contemplation.

But Buddhism did not travel alone to Japan; it brought with it Chinese culture. Over the next two centuries, monks, artists and scholars went to China to study religion, art, music, literature and politics, all of which brought great advances to Japanese culture. As a result, Buddhism became embroiled in the political struggles of the Nara and Heian eras, when weak emperors used Buddhist and Chinese culture to enhance their own power and level of cultural sophistication, and to reduce the influence of their Shintoist rivals. The balance of power between buddhas and kami also shifted: kami were regarded as being prone to rebirth, from which they could be released by Buddhist sutras. To this end, Buddhist temples were built next to Shinto shrines, and statues and regalia placed on Shinto altars to help raise the kami to the level of buddhas. Eventually, some kami became the guardians of temples, while buddhas were regarded as the prime spiritual beings.

Up until the end of the twelfth century, Japanese Buddhism was largely restricted to a small, generally aristocratic minority who had been initiated into the faith. However, at this time the dominant sect, Tendai , split into various new sects , notably Jodo, Jodo Shinshp, Nichiren and Zen Buddhism, which each appealed to different sections of the population. The first two in particular were simple forms of the faith which enabled Buddhism to evolve from a religion of the elite to one which also appealed to the population en masse. The Nichiren sect had a more scholastic approach, while Zen's concern for ritual, form and practice attracted the samurai classes and had a great influence on Japan's traditional arts. Almost all contemporary Japanese Buddhism developed from these sects, which are still very much in existence today .

From the fifteenth century, however, Shinto started making a comeback. In reaction to the absorption of the indigenous faith into this foreign religion, various Shinto sects revived the ascendancy of kami over buddhas, ending the idea that they were merely Japanese manifestations of buddhas. This process came to a head after the 1868 Meiji Restoration, when Shinto was declared the national faith. Most Buddhist elements were removed from Shinto shrines and destroyed, and Buddhism was suppressed until the end of World War II when religious freedom returned to Japan. Nowadays Buddhism and Shinto coexist peaceably once again and share the vast majority of their followers.