Minamoto no Yoritoshi (源頼俊)
MINAMOTO no Yoritoshi (year of birth and death unknown) was a busho (Japanese military commander) in the late Heian period. He was the first son of Kaga no kuni no kami (Governor of Kaga Province) MINAMOTO no Yorifusa who belonged to the legitimate line of Yamato-Genji (Minamoto clan). According to the description of "Sonpi Bunmyaku" (a text compiled in the fourteenth century that records the lineages of the aristocracy), he was an adopted child of his grand father MINAMOTO no Yorichika. His lawful wives included the daughter of Harima no kuni no kami (the governor of Harima Province) FUJIWARA no Sadasuke (a son of FUJIWARA no Tokitaka), who belonged to the Kajuji line of Northern House of Fujiwara clan. His children included MINAMOTO no Yorikaze, MINAMOTO no Yoriharu, and MINAMOTO no Yorikage. His official court ranks were Jugoinoge (Junior Fifth Rank, Lower Grade), kebiishi (official with judicial and police powers), Saemon no jo (third-ranked officer of the Left Division of Outer Palace Guards), Kazusa no suke (Assistant Governor of Kazusa Province), and Mutsu no kami (the governor of Mutsu Province).
The first record of the military art of kasagake (horseback archery competition), which was considered to be essential for warriors, is when it was held by retainers of Yoritoshi who guarded the Fujiwara clan in 1057 in the Emperor Goreizei's era in Kizu-kohan Riverside in Kyoto during the round trip to Nara.
He was assigned to Mutsu no kami in 1067. In 1070, he went on conquest of Ezo (northerners) by an imperial order of Emperor Gosanjo, and with help of KIYOHARA no Sadahira, conquered around Tsugaru and Shimokita Peninsula that were under control of Ezo. According to the petition letter of Yoritoshi written in February 4, 1071, there was an incident that very atrocious persons including Sani (courtier without post) FUJIWARA no Motomichi who had his territory in southern part of Mutsu Province denied kanmotsu (tribute goods paid as taxes or tithes) and kuji (public duties) and bereaved the seal of province and the key to the provincial treasury during the conquest.
He subdued this incident with help of MINAMOTO no Yoshiie who was assigned to Shimotsuke no kuni no kami (the governor of Shimotsuke Province) by an imperial order. It is thought that Motomichi caused this incident to hamper Yoritoshi who received the will of Yoshiie from extending power over Mutsu. In the same letter, there is a description 'araebisu (crude warrior from the eastern parts of the country) rises up in arms and the people riot,' which indicates that Ezo still did not submit to control of the Imperial Court.
Since 1067, he subdued Ezogawakeshima araebisu and monk soldiers of Heinana-mura and extended the eastern end (northern end) of Japan to Tsugaru Straits with help of the Dewa-Kiyohara clan. This large scale project continued until 1074, which was later called the Battle against Ezo in the Enkyu era.
In this battle, Yoritoshi did not receive any significant Onsho (reward grants), but KIYOHARA no Sadahira, whose military force he relied upon, was assigned to Chinjufu shogun (Commander-in-Chief of the Defense of the North) Jugoinoge (Junior Fifth Rank, Lower Grade). His father, KIYOHARA no Takenori, was also Chinju-fu shogun. After that, Yoritoshi, who went back to Kyoto, rendered military exploits under an imperial order to capture soto (priests) of Onjo-ji Temple who attempted to cause a disturbance by appealing directly to gosho (Imperial Palace) on November 3, 1181.
In the moshibumi utsushi (copy of general term for a request or petition submitted by a lower authority to a higher) by the former Mutsu no kami MINAMOTO no Yoritoshi, which they say he wrote to request reward in the Battle against Ezo in the Enkyu era, there is a description '前陸奥守従五位上源朝臣頼俊誠惶誠恐謹言、…依 綸旨召進武蔵国住人平常家、伊豆国●●●散位惟房朝臣、条条之勤不恥先蹤者也…,' as well as description of great success of Tsuneie TOYOSHIMA in the Battle against Ezo in the Enkyu era.