Belief in Buddhism grew greatly in the Heian era.
Belief in Buddhism grew greatly in the Heian era.

The Heian period in Japanese history lasted from 794 to 1185. Buddhism spread widely in Japan during this era. Although the religion had been introduced earlier, it was in this period that the schools of Tendai and Shingon took shape and engaged with the native religion of Shintoism to create new religious beliefs.

Shingon

Shingon, or "true word," Buddhism was introduced to Japan from China in the ninth century. This sect emphasized the belief that the true wisdom of the Buddha cannot be understand through his words, and therefore studying Buddhist texts alone cannot help an individual reach enlightenment. Shingon Buddhists believed in understanding the wisdom of the Buddha through esoteric rituals that involved gestures, body language and mental concentration. In Japan, this religious doctrine was spread by a follower of Buddhism named Kukai.

Tendai

Introduced to Japan by a monk named Saicho who traveled to China expressly to study this type of Buddhism, the Tendai school was the other new Buddhist belief system spreading through Japan in the Heian period. The principles of Tendai Buddhism focus on the "triple truth" that all things are inherently empty of substance, are temporary and occupy these two states simultaneously. The beliefs of this school were more in line with traditional Mahayana Buddhism, though Japanese followers didn't widely embrace Saicho's teachings until after his death, according to Encyclopaedia Britannica.

True Pure Land

True Pure Land Buddhism also grew in popularity during the Heian era. This sect emphasized the importance of the Buddha of infinite light, called Amida Buddha. These Buddhists believed that if they followed the path of Amida by helping other people and living a virtuous life, they would be reborn into Amida's Pure Land where they would become Buddhas themselves. The teachings of this sect were transmitted to Japan through Tendai Buddhism, but following the Heian period, the two movements split.

Shintoism

Although Shintoism is a folk religion that differs from region to region, it is the native religion of Japan. Interactions with Buddhism during the Heian period changed both faiths. Buddhist philosophy and morality became entwined with Shinto belief, and occasionally Buddhist monks acted as the heads of Shinto shrines which, in some cases, had merged with Buddhist temples. The BBC notes that for some Japanese citizens in the Heian period, belief in Shintoism and Buddhism became one in the same.