From Monitor to Father-in-Law: The Twenty Years of Tokimasa and Yoritomo

In the spring of 1160 (Eiryaku 1), at Hōjō in Izu Province (the modern Izunokuni City, Shizuoka Prefecture).

Yoritomo (then fourteen), the third son of Minamoto no Yoshitomo defeated at the Heiji Rebellion, was exiled to Izu by Taira no Kiyomori.

The one who came to bear the role of monitor to Yoritomo was the local Izu warrior Hōjō Tokimasa.

For the twenty-two-year-old Tokimasa, this monitor role was no more than a duty as one member of the Izu middle-and-small local families.

For the next twenty years, this relationship would develop in a direction that fundamentally changed Japanese political history.

The Hōjō house of 1160 was no more than one of several middling-and-small warrior bodies in Izu Province.

Its mobilizable strength was around several hundred, its holdings within a part of Izu, and it survived quietly under the umbrella of the Taira lineage.

In the generation of Tokimasa's father Tokikata, the family's retainer relation to the Taira had advanced, and in that connection they had been assigned the monitor role for the exile of Izu.

Tokimasa personally had no special ambition, and this monitor role too was a dutiful assignment.

Around 1177, the situation changed dramatically. Tokimasa's eldest daughter Masako (this site's id 24, then around twenty-one) and Yoritomo (around thirty-one) secretly married without passing through Tokimasa's intent.

According to the Azuma Kagami, Tokimasa flew into rage and tried to marry Masako to another warrior (said to be Yamaki Kanetaka), but Masako ran out of her father's house on a rainy night and ran to Yoritomo.

Tokimasa finally had no choice but to accept the fait-accompli marriage.

In August 1180, when Yoritomo raised troops in Izu in response to Prince Mochihito's call to arms, Tokimasa did not hesitate to side with Yoritomo.

As son-in-law's father, he was already in the position of sharing fate with Yoritomo's victory or defeat.

From the early-uprising defeat at Ishibashiyama, through the flight to the Bōsō Peninsula, and up to the gathering of the Kantō warrior body and the entry into Kamakura — for several months, Tokimasa moved as a core staff to Yoritomo.

Tokimasa, who had met Yoritomo as monitor in 1160, was twenty years later at the center of the founding of the Kamakura shogunate.

His daughter Masako's secret marriage was the direct starting point of this leap.