From the emperor Richū (400-405) to the emperor Senkwa (536-539), the chronicles record a series of fratricidal struggles for the succession to the throne upon the death of the various sovereigns. Which, however, seem to have reigned with clemency and with awareness of the needs of the people. Only two are pointed to the execration of posterity: Yūryaku (457-479), who ascended the throne through two crimes, and Muretsu (499-506), known for his strangeness and cruelty, whom he suffered with his life after a short reign..
Under the 29th emperor Kinmyō (540-571), with the introduction of Buddhism, Japanese civilization entered a new, very fruitful phase. In 552, the king of Kudara, one of the Korean tributary states of Japan, sent the emperor a statue of Buddha, perhaps of the Buddha Amida, with some s ū between. Minister Soga Iname immediately proved in favor of the acceptance of the new doctrine while the Mononobe, guardians of the palace, thwarted it, claiming that it would arouse the indignation of the indigenous deities. An epidemic, which broke out shortly after, seems to prove them right; the statue is made to disappear and the new faith suffers a check; but only for a short time, since the struggle, apparently religious, but in fact of supremacy, immediately engaged between the Soga and the Mononobe and ended in 587 with the defeat of the latter on Mount Shigi, ensured protection and diffusion of the new doctrine. In 588 Korea sent religious, scholars, doctors, astrologers, and with them a whole stream of culture pervaded the country. The temples begin to be built at the end of the century. YOU; a census of 623 gives 46 existing ones, with 816 priests and 529 religious, throughout the Empire. The empress Suiko (593-628), placed on the throne by her uncle Soga Umako, who became omnipotent after the victory over the Mononobe, and, above all, her nephew, the prince Shōtoku-taishi (572-621) played a major part in this rapid development.), a fervent religious and man of letters.
On the death of Suiko (628), Soga Umako, flanked by his son Iruka, prevented Yamashiro, son of Shōtoku-taishi, from rising to power, to whom he destined the nephew of the deceased, Jomei (629-641); and, after this one, his widow Kōgyoku (642-645). Under her reign, Iruka, wanting to give her a blood relative as her successor, decided to get rid of Yamashiro, the only obstacle, and had him assassinated (643). Tired of the Soga tyranny, the courtiers plotted a conspiracy that led to the killing of Iruka (645) and the abdication of Kōgyoku in favor of his brother Kōtoku (645-654).
According to Justinshoes, the reign of this ruler marks a turning point in the history of indigenous civilization, as Japan enters an era of very important social reforms that will give it an administration modeled on the contemporary Chinese one of the T’ang (620-907). The limits of the provinces and districts were defined, at the head of which officials were appointed, a census was carried out, deciding to repeat it every six years, the lands were divided among the peasants, the use of eras was established (neng ō) in the calculation of time, etc. The main architect of these reforms, continued under Kōtoku’s successors, was Nakatomi-no-Kamatari, one of the leaders of the conspiracy against the Soga, who, created prime minister by the Emperor Tenchi (662-671), had, shortly before to die (670), the permission to take the name of Fujiwara (v.), which a group of writers, artists, statesmen, generals, will soon make illustrious. The adoption of the complicated Chinese bureaucratic system made difficult the changes of capital that always occurred at the death of every sovereign, changes that originated from the belief that death made impure, and therefore it was necessary to abandon the house and the place of death and to transport one’s penates elsewhere. It was under the Empress Genmyō (708-714) that a new city was founded, Nara, and it was established that it would forever remain the capital of the empire. In 794, however, the emperor Kwanmu (782-808), transported it to Kyōto, which will permanently remain the residence of the court until 1868.
The Fujiwara. – Kwanmu is a good figure of organizer. He took care of education, services and works of public utility, agriculture, abolished sinecures and instituted for the emperors the posthumous name, different from the one they had in life, by which they are known in history. Under his successors progress, especially cultural progress, increases and prosperity introduces luxury which refines tastes and effeminate souls; the court becomes a place of delight where the emperors, amidst leisure and indulgence, forget the care of the government. The Fujiwara, whose influence was gradually increasing, took advantage of this. Already the emperor Montoku (851-858) married to a Fujiwara, had granted privileges to the members of this family, who from the time of Kamatari held, by custom, the office of prime minister. kwampaku or palace master became their monopoly. With much tact and skill, qualities that the Fujiwara had in the highest degree, they created the custom of having the emperor choose his wife from among the women of his own family; thus, over time, mothers and wives of the imperial princes were Fujiwara. Their power grew out of all proportion, and the most important offices fell into their hands. But not satisfied with this, they introduced another use which was to put the throne at their mercy. At the birth of an imperial prince, the Fujiwara took him with them to educate him and on his accession to the throne, at an early age, his maternal grandfather, also a Fujiwara, became regent (sessh ō, office created at the end of the century. IX) in the name of the emperor. The sovereign child was raised in a nerve-wracking atmosphere and amidst all sorts of distractions, then, having come of age, or even earlier, at the slightest sign of aspiration for independence, he was forced to abdicate, and often advised to take the religious habit. Such subtlety of intrigue ensured the Fujiwara for about four centuries an absolute supremacy which had its golden period under the famous minister Michinaga (966-1027), son-in-law of three emperors. Against any attempt at opposition they acted promptly and energetically: for example, the case of the minister Sugawara Michizane (845-903), who, for trying to open his eyes to the emperor Daigo (898-930), was exiled.
After Michinaga, the power of the Fujiwara starts at sunset; on the one hand the ease and softness they had used to annihilate the imperial authority, on the other the rise of the great military families, which, aware of their strength, aspired to power, soon led to its decline.