Rebellion of Taira no Masakado

Masakado belonged to the Kanmu Taira, descendants of Emperor Kanmu reduced to commoner status. His grandfather Takamochi had come east as vice-governor of Kazusa at the end of the 9th century, and his father Yoshimochi had served as chinjufu shōgun, commander of the frontier headquarters in Mutsu. As a young man Masakado served the regent Fujiwara no Tadahira in the capital without gaining any significant office. Back in Shimōsa he quarrelled with his uncles and their in-laws — over a woman, according to the Shōmonki, which dates the start of the quarrel to 931, or over his inheritance, according to later tales. In the second lunar month of 935 the sons of Minamoto no Mamoru ambushed him at Nomoto; they were killed, and his uncle Kunika also died, either in the fighting or in the fires that Masakado set. Summoned to the capital on Mamoru’s complaint, Masakado was pardoned in 937 in an amnesty for the coming of age of Emperor Suzaku, but the feud flared up again as soon as he returned.

In 939 he tried to mediate a dispute in Musashi between the acting governor Prince Okiyo and the deputy governor Minamoto no Tsunemoto on one side and a district official on the other; Tsunemoto fled to the capital and accused him of rebellion, but Masakado sent certificates from five provincial offices, and the court cleared him and punished Tsunemoto for false accusation. Masakado then sheltered Fujiwara no Haruaki, a fugitive wanted by the authorities of Hitachi, and on 3 January 940 marched on the Hitachi provincial office: in the traditional account his band of just over a thousand men routed 3,000 provincial troops, the deputy governor surrendered and the seals and keys of the province were seized. On Prince Okiyo’s advice — that taking all of the Bandō would bring no heavier punishment than taking one province — he occupied Shimotsuke on 22 January and Kōzuke on 26–30 January. Citing an oracle of Hachiman and, in some accounts, the spirit of Sugawara no Michizane, he proclaimed himself shinnō, ‘New Emperor’, appointed governors to the eastern provinces and set up his seat at Iwai. Because the Japanese year Tengyō 2 ended only in February 940, the revolt is often dated 939–940.

The court, alarmed also by the rising of Fujiwara no Sumitomo in the Inland Sea, ordered prayers, promised rewards to anyone who would subdue the rebel and on 29 February appointed Fujiwara no Tadafumi general to pacify the east, but his army arrived too late. Masakado had sent most of his men home to their fields; his cousin Taira no Sadamori, Kunika’s son, and Fujiwara no Hidesato, a pacification officer of Shimotsuke, gathered some 4,000 men, burned Iwai on 24 March and on 25 March caught Masakado with about 400 followers near his base. An arrow struck him in the forehead, and his head was taken to the capital and exposed. The Shōmonki, an account of the rising written perhaps as early as the 940s, is the main source for it; legends grew up around Masakado, and his spirit was later revered at the Kanda Shrine in Edo. The revolt showed that the court could not assert its authority in the east without provincial warriors, and marked the rise of those warriors, whose descendants dominated the east in the following centuries.