Women took an active part in the religions of early Japan. From ancient times women were Shinto shamans. Often a miko or a Shinto princess was called upon in difficult cases to try to establish the truth. After going into a trace and being possessed by the god, the kami would then speak though the miko's voice. Also, women participated equally in Japan's festivals and celebrations. Some, such as the festival of the Maid Star (the Tanabata festival), were directed principally toward women.

When Buddhism first appeared it appealed particularly to upper-class women. The convents offered them an alternative to marriage and provided leadership roles through the office of abbess. Visits to temples offered others an escape from the confines of their houses. At the same time, Buddhism lessened women's status by portraying them as dishonest, deceitful, and neglectful of religious duties.

By the 12th century many Japanese were adherents of Amidism. It was felt that only Amida's grace could help in this age of degenerating social and political structures. Amida's appeal was the idea that belief alone, and not intense self-discipline and self-power, could assure one's escape from the painful cycles of birth and rebirth. The Monk Honen claimed that by repeating the Amida name of Buddha, there would be no distinction between men and women nor between the mighty and the weak. Later, the more violent Lotus sect repudiated this; "No women are to be found in paradise. Women will have to first be reborn as men." Beliefs of women's inherent sinfulness increased as time went on.

from http://www.womeninworldhistory.com/sample-08.html