The fact would appear to be that Hojo Yoshitoki's intrigues were too subtle for the perception of Sanetomo or even of the lady Masa. Yoshitoki had learned all the lessons of craft and cunning that his father could teach and had supplemented them from the resources of his own marvellously fertile mind. His uniformly successful practice was to sacrifice the agents of his crimes in order to hide his own connexion with them, and never to seize an opportunity until its possibilities were fully developed. Tokimasa had feigned ignorance of his daughter's liaison with Yoritomo, but had made it the occasion to raise an army which could be directed either against Yoritomo or in his support, as events ordered. There are strong reasons to think that the vendetta of the Soga brothers was instigated by Tokimasa and Yoshitoki, and that Yoritomo was intended to be the ultimate victim.
This was the beginning of a long series of intrigues which led to the deaths of Yoriiye and two of his sons, of Hatakeyama Shigetada, of Minamoto Tomomasa, of Wada Yoshimori, and of many a minor partisan of the Yoritomo family. In the pursuit of his sinister design, there came a time when Yoshitoki had to choose between his father and his sister. He sacrificed the former unhesitatingly, and it is very probable that such a choice helped materially to hide from the lady Masa the true purport of his doings. For that it did remain hidden from her till the end is proved by her failure to guard the life of Sanetomo, her own son, and by her subsequent co-operation with his slayer, Yoshitoki, her brother. A mother's heart would never wittingly have prompted such a course.
There is a tradition that Sanetomo provoked the resentment of Masa and Yoshitoki by accepting high offices conferred on him by Kyoto—chunagon, and general of the Left division of the guards—in defiance of Yoritomo's motto, "Wield power in fact but never in name," and contrary to remonstrances addressed to him through the agency of Oye no Hiromoto. There is also a tradition that, under pretense of visiting China in the company of a Chinese bonze, Chen Hosiang, he planned escape to the Kinai or Chugoku (central Japan), there to organize armed resistance to the Hojo designs. But it is very doubtful whether these pages of history, especially the latter, should not be regarded in the main as fiction. Sanetomo was too much of a littérateur to be an astute politician, and what eluded the observation of his lynx-eyed mother might well escape his perception.
In 1217, Yoshitoki invited Kugyo from Kyoto and appointed him to be betto of the shrine of Hachiman (the god of War) which stood on the hill of Tsurugaoka overlooking the town of Kamakura. Kugyo was the second and only remaining legitimate son of Yoriiye. He had seen his father and his two brothers done to death, and he himself had been obliged to enter religion, all of which misfortunes he had been taught by Yoshitoki's agents to ascribe to the partisans of his uncle, Sanetomo. Longing for revenge, the young friar waited. His opportunity came early in 1219. Sanetomo, having been nominated minister of the Left by the Kyoto Court, had to repair to the Tsurugaoka shrine to render thanks to the patron deity of his family. The time was fixed for ten o 'clock on the night of February 12th. Oye no Hiromoto, who had cognizance of the plot, hid his guilty knowledge by offering counsels of caution. He advised that the function should be deferred until daylight, or, at any rate, that the shogun should wear armour. Minamoto Nakaakira combatted both proposals and they were rejected. Sanetomo had a vague presentiment of peril. He gave a lock of his hair to one of his squires and composed a couplet:
Though I am forth and gone,
And tenantless my home;
Forget not thou the Spring,
Oh! plum tree by the eaves.
Then he set out, escorted by a thousand troopers, his sword of State borne by the regent, Yoshitoki. But at the entrance to the shrine Yoshitoki turned back, pretending to be sick and giving the sword to Nakaakira. Nothing untoward occurred until, the ceremony being concluded, Sanetomo had begun to descend a broad flight of stone steps that led from the summit of the hill. Then suddenly Kugyo sprang out, killed Sanetomo and Nakaakira, carrying off the head of the former, and, having announced himself as his father's avenger, succeeded in effecting his escape. But he had been the agent of Yoshitoki's crime, and his survival would have been inconvenient. Therefore, when he appealed to the Miura mansion for aid, emissaries were sent by the regent's order to welcome and to slay him. Sanetomo perished in his twenty-eighth year. All accounts agree that he was not a mere poet—though his skill in that line was remarkable—but that he also possessed administrative talent; that he strove earnestly to live up, and make his officers live up, to the ideals of his father, Yoritomo, and that he never wittingly committed an injustice.
ESTABLISHMENT OF THE HOJO REGENCY
Thus, after three generations occupying a period of only forty years, the Minamoto family was ruined, and the reins of power were effectually transferred to Hojo hands. It would seem natural, in the sequence of events, that the office of shogun should now descend to the Hojo. But Yoshitoki understood that such a measure would convict him of having contrived the downfall of Yoritomo's progeny in Hojo interests. Therefore a step was taken, worthy of the sagacity of the lady Masa and her brother, the regent. The Bakufu petitioned the Kyoto Court to appoint an Imperial prince to the post of shogun. That would have invested the Kamakura Government with new dignity in the eyes of the nation. But the ex-Emperor, Go-Toba, upon whom it devolved to decide the fate of this petition, rejected it incontinently.
His Majesty, as will presently be seen, was seeking to contrive the downfall of the Bakufu, and the idea of associating one of his own sons with its fortunes must have revolted him. In the face of this rebuff, nothing remained for the Bakufu except recourse to the descendants of the Minamoto in the female line. Yoritomo's elder sister had married into the Fujiwara family, and her greatgrandson, Yoritsune, a child of two, was carried to Kamakura and installed as the head of the Minamoto. Not until 1226, however, was he invested with the title of shogun, and in that interval of seven years a momentous chapter was added to the history of Japan.