Kamakura shogunate founded by Minamoto no Yoritomo
The Kamakura shogunate (Japanese: 鎌倉幕府, Hepburn: Kamakura bakufu) was the feudal military government of Japan during the Kamakura period from 1185 to 1333.The Kamakura shogunate was established by Minamoto no Yoritomo after victory in the Genpei War and appointing himself as shōgun. Yoritomo governed Japan as military dictator from the eastern city of Kamakura with the emperor of Japan and his Imperial Court in the official capital city of Heian-kyō (Kyoto) as figureheads. The Kamakura shōguns were members of the Minamoto clan until 1226, the Fujiwara clan until 1252, and the last six were minor princes of the imperial family. The Hōjō clan were the de facto rulers of Japan as shikken (regent) of the shōgun from 1203. The Kamakura shogunate saw the Jōkyū War in 1221 and the Mongol invasions of Japan under Kublai Khan in 1274 and 1281. The Kamakura shogunate was overthrown in the Kenmu Restoration under Emperor Go-Daigo in 1333, re-establishing Imperial rule until Ashikaga Takauji and his offsprings overthrew the imperial government and founded the Ashikaga shogunate in 1336 (Nanboku-chō period).History
Establishment
Historically in Japan, the power of civilian government was primarily held by the ruling emperor of Japan and their regents, typically appointed from the ranks of the Imperial Court and the aristocratic clans that vied for influence there. Military affairs were handled under the auspices of the civil government.
From 1180 to 1185, the Genpei War was fought between the Taira and Minamoto clans as part of a longstanding violent rivalry for influence over the Emperor and his court. Minamoto no Yoritomo defeated the Taira clan, but in his victory seized power from the civil aristocracy, politically relegating the Emperor and his court to symbolic figureheads. In 1192, Yoritomo and the Minamoto clan established a military government in Kamakura.The Hōjō Regency
Yoritomo unexpectedly died in an accident in 1199, leaving the Minamoto clan weakened. Hōjō Tokimasa, the father of Yoritomo's widow, Hōjō Masako, and former guardian and protector of Yoritomo, claimed the title of regent (shikken) to Yoritomo's son Minamoto no Yoriie, eventually making that claim hereditary to the Hōjō clan. At the same time, Hōjō Masako maneuvered herself into such a powerful, albeit informal, position that people began calling her the "nun shogun" in the place of her son Yoriie. As Minamoto no Yoriie grew older, however, he attempted to exert real power, resulting in a power struggle with the Hōjō clan of his own mother. These conflicts caused considerable tensions within the shogunate. In 1201, the Jo clan unsuccessfully attempted to overthrow the Minamoto clan in the Kennin Rebellion. Eventually, Tokimasa deposed Yoriie, backed up his younger brother, Minamoto no Sanetomo, as a new shōgun, and assumed the post of shikken. Sanetomo was only twelve at this point, and accordingly power factually rested with his mother Hōjō Masako. The Minamoto remained the titular shōguns, with the Hōjō holding the real power. In 1204, loyalists of Yoriie attempted an uprising to topple the Hōjō domination, but the latter defeated the rebels and assassinated Yoriie.In 1205, Hōjō Tokimasa attempted to depose Sanetomo, hoping to install his son-in-law as new shogun. However, his daughter Hōjō Masako saw this as threat to her own status; she arranged the pretender's murder and banished her father to a monastery. In 1219, Sanetomo was assassinated by his nephew Kugyō. Since Sanetomo died childless, the line of shōguns from the Minamoto clan ended with him. From this point onwards, the Hōjō were in total control. With Sanetomo's death in 1219, his mother Hōjō Masako continued to serve as the shogunate's real center of power. As long as she lived, regents and shōguns would come and go, while she stayed at the helm. Since the Hōjō family did not have the rank to nominate a shōgun from among its members, Masako had to find a convenient puppet. The problem was solved by choosing Kujo Yoritsune, a distant relation of the Minamoto, who would be the fourth shōgun and figurehead, while Hōjō Yoshitoki would take care of day-to-day business. However powerless, future shōguns would always be chosen from either Fujiwara or imperial lineage to keep the bloodline pure and give legitimacy to the rule. This succession proceeded for more than a century.As a result, the Kamakura shogunate rested on an unusual pyramid of regents and de facto usurpation: The true rulers, namely the Hōjō regents, had usurped power from the Minamoto, who had usurped it from the Emperor, descending from Emperor Kōkō, who usurped it from the children of Emperor Seiwa. At the same time, the regents, shoguns, and emperors all still maintained their nominal positions and existed alongside each other. The regime nonetheless proved to be stable enough to last a total of 135 years, 9 shōguns and 16 regents.In 1221, Emperor Go-Toba tried to regain power in what would be called the Jōkyū War (承久の乱, Jōkyū no Ran), but the attempt failed. The power of the Hōjō remained unchallenged until 1324, when Emperor Go-Daigo orchestrated a plot to overthrow them, but the plot was discovered almost immediately and foiled.