The fall of Yoritomo and the rise of the Hojo clan

Yoritomo passed away in 1199 when he was 53 years old. It is said that he fell off a horse that triggered his death. But there are some other theories such as assassination. Anyway it is very strange that the cause of death of such an important person is obscure. Personally I doubt that Tokimasa Hojo plotted Yoritomo's death. His elder son Yoriie succeeded Yoritomo when he was 18.The young Shogun was an iconoclast and neglected Yoritomo's vassals. So, Tokimasa set up a council system of 13 vassals to stop Yoriie's autocracy three months after his succession to the shogunate. Kagetoki Kajiwara and Yoshikazu Hiki who were supporters of Yoriie among vassals were killed in 1200 and 1203 respectively and Yoshiie was detained in a monastery of Shuzen-ji Temple in Izu.In 1204 Yoriie was killed. After Yoshiie was ousted to Izu, Sanetomo who was the younger son of Yoritomo became Shogun at the age of 12. Finally Tokimasa became the first regent and assume control of the Kamakura government. There was another tragedy for Yoritomo family. In 1219 Sanetomo was assassinated by his nephew Kugyo who was Yoriie's son and Kugyo was killed soon after the assassination. At this moment Yoritomo lost all of his heirs apparent.
Yorotomo's grave is to the east of Tsurugaoka Hachimangu Shrine.Kagetoki Kajiwara's grave is at a strange site. Get off an Ofuna monorail train at Shonan-Fukazawa station. Within five minutes' walk you will arrive at Fukazawa Elementary School. Ask a security guard to open the gate and you will know where it is if you ask him politely. It is at the back of a school building.
Yoshikazu Hiki and his family's memorial site is Myohon-ji Temple.