Kamo no Tadayuki (賀茂忠行)

KAMO no Tadayuki (year of birth and death unknown).
According to one theory, he (year of birth unknown - 960?) was an Inyoka (the Yin and Yang school of philosophy)
He was also known as ABE no Seimei's master.
He was the son of KAMO no Ebito or KAMO no Mineo

He was an excellent practitioner of the Yin and Yang (positive and negative, light and shade) art, a concept originated in China based the durability of all the existences in the universe, and he gained an absolute trust of the Emperor of that time. Especially, he was good at 'sekifu' (projection or seeing an object through a cover), and he once performed it in front of the Emperor. It is said that he picked out ABE no Seimei and taught him the essence of Onmyodo (yin-yang philosophy) as if he 'poured the whole water of a bottle into another ("Konjaku Monogatari (Shu) " [The Tale of Times Now Past]). He consecutively held various posts such as Tamba no Gon no suke (supernumerary vice governor of Tanba Province) and Tajima no Suke (vice governor of Tajima Province). Although there is no reliable proof, some say that he also took charge of Onmyo no kami (Director of Onmyoryo, or Bureau of Divination). KAMO no Yasunori and YOSHISHIGE no Yasutane were his sons.

Achievements
KAMO no Tadayuki was very good at 'sekifu,' a practice to guess an article inside a cover, and in the Engi era, he was ordered by Emperor Daigo, the emperor of that time, to show his skill.
In front of Tadayuki, a octagonal box was placed, and he accurately told 'there is a juzu (rosary) of crystal beads linked together with a vermilion string.'
He was highly prized as '天下に並ぶもの無し''a man unrivaled' ("Konjaku Monogatari").

KAMO no Tadayuki in narrative stories

According to the '安倍晴明忠行に随いて道を習いし語''Story of ABE no Seimei's learning the way under Tadayuki' in the "Konjaku Monogatari (Shu)," one day, when Tadayuki was on the way back home from the Imperial Palace, he was waken up by young attendant ABE no Seimei, who was outside the gissha (ox-drawn carriage). When Tadayuki looked out of the window, he saw Hyakki yagyo (night parade of one hundred demons), and since this experience, in which he had a narrow escape, he gave Seimei a special affection.

According to the 'Story of KAMO no Tadayuki's teaching the way to his son Yasunori' in the same book, when Tadayuki went to a nobility's residence to purify the residence, Tadayasu took his son with him because his little son, KAMO no Yasunori said that he would like to accompany him. The ritual finished smoothly, and on the way back, Yasunori talked to his father that he witnessed uncanny-looking figures that were eating the offerings in front of the altar and playing with them. Then, he foresaw his son's unusual capacity and taught the Onmyodo to his son.

The position of KAMO no Tadayuki in the history of Onmyodo

KAMO no Tadayuki played an important role in the history of Onmyodo
Until then, the three department of Onmyoryo (Bureau of Onmyodo: a government office that had jurisdiction over calendar preparation, astronomy, divination, etc.) (Onmyodo), Tenmondo (astrology), Rekido (learning of the calendar) and Onmyodo, were divisively undertaken by each specialists; however, KAMO no Tadayuki, who was a Rekika (scholar of Rekido), controlled all the three department beyond these scopes of duties and established the Kamo clan, the family that produced yin yang philosophers. This led to the monopoly of Onmyoryo and Onmyodo by the Kamo clan and the Abe clan, which was Tadayuki's disciple line. ABE no Seimei, who was the disciple of Rekika (scholar of learning of the calendar) KAMO no Tadayuki, ascended to Onmyoji (yin yang master) after holding the position of Tenmon tokugyo no sho (researcher of the astrology), and finally up to Tenmon hakase (master of astrology), and later, he took over the title of Soke (head of the school) of Tenmondo (astrology) from Tadayuki's son, KAMO no Yasunori.

In the background of the integration of the three departments of Onmyodo that KAMO no Tadayuki achieved, there was a circumstance, in which various updated theories and philosophies related to the Taoist theory of the five elements were no longer conveyed to Japan due to the abolishment of the Kento-shi (Japanese envoy to Tang Dynasty China) by Michizane SUGAWARA in 894. Since no up-to-date information came to Japan from the continent, they were obliged to teach and use the existing information.
Therefore, students of the Onmyodo were limited to the descendents of the secular officials who had been in service since the outset of the Onmyoryo's establishment, and the training was conducted in closed environment,
As a result, in the period in which KAMO no Tadayuki played an important role, the staffs of Onmyoryo had been reduced in number. Influenced by this, within the Onmyoryo, they had to take charge of additional posts of more than two departments, which was originally prohibited, or they had no choice but to cope with the shortage of capable persons by using those holding the positions of 'gon' (provisional positions, such as Gon no tenmon hakase [provisional master of astrology] or Gon no reki hakase [provisional master learning of calendar], which were originally set up as a kind of auxiliary or honorary post.
The Kamo clan stepped into the Onmyoryo, where the positions had been hereditary and the education had been closed until then, as a 'new comer.'
And in addition to the element of jujutsu (an occult art) derived from Taoism, which was the basis of the Onmyodo, he adopted diversified elements of theistic religions including Tantric Buddhism, which was flourishing in that period, and religious belief related with jujutsu (an occult art).
He also carried out the functional change of Onmyodo shifting the emphasis from 'art' to 'religion and jujutsu.'
Although the Onmyoryo had been degraded to a mere 'institution of authorization' or 'executing institution of everyday rites and rituals,' serving only to testify the authority of the Emperor under the Ritsuryo system (an ancient system of centralized governance based on the Ritsuryo code), he succeeded in finding a new way not only in the Onmyoryo but also in the philosophy of Onmyodo. Such achievements lead him to gain an enormous support of the Emperor and the people of influence, and shortly he began to distinguish himself in the Onmyoryo, where only a reduced number of officials were remained. It is said that, in addition, the fact that the officials had to hold additional posts of departments due to the shortage of capable government officials in Onmyoryo helped the Kamo clan, whose talent and position had been well recognized, to monopolize the principal departments of the Onmyoryo all at once.

Same as the Kamo clan, the Abe clan, which was the disciple line of the Kamo clan and the astronomer family, also shortly succeeded in having a large influence within the Onmyoryo, thanks to the shortage of talented people. It is said that the Abe clan also gradually established its authority by promoting the basic policy change in the Onmyoryo in cooperation with the Kamo clan.