Ukei (Ancient Divination) (うけい)
Ukei is the act of divination practiced in ancient Japan. It is written as 宇気比 (phonetic representation of the word), 誓約 (pledge), 祈 (prayer), 誓(vow), etc. For a question (e.g. Does Susano have bad intentions?), an act was performed, with the vow that the answer would be in the affirmative if it produced a certain result, but in the negative if it did not. Depending on the result of an act, people determined whether a proposition was fortunate or unfortunate, right or wrong, or successful or unsuccessful.
Such a pledge is often made in critical moments in Japanese mythology.
Ascending from the earth to the celestial world of Takamagahara, Susano pledges to Amaterasu that he has no bad intentions of conquering the heavens (Susano's Pledge to Amaterasu). In this tale, the two gods exchange their own object with each other to determine whether or not Susano has bad intentions on the basis of the gender of children who are born out of the objects. In the episode on the restoration of the country of Ashihara no Nakatsukuni, Takamimusubi sees the arrow he gave Amenowakahiko flying out from the earth. He resorts to pledge to determine whether or not the arrow was used to pacify the country. He shoots the arrow back at the earth, with the vow that it will not hit Amenowakahiko if it is meant for pacification, and hit him if it is not. It hits Amenowakahiko right in the chest, killing him. After his divine descent, Ninigi the grandson of Amaterasu marries Konohana no Sakuyabime who becomes pregnant in a single night. However, he suspects her virginity. Thereupon she sets fire to a childbirth hut where she is going to give birth, pledging that the child will not be born if it is not by Ninigi, but it will if by him. She successfully gives birth to the child.