Stories of the Japanese 00561 [Early Kamakura Period] The Revenge of the Soga Brothers: Territorial Usurpation

The Kudo family had split between the adopted son, Ito Suketsugu, and the grandson, Kawazu Sukechika, and Kawazu Sukechika felt deeply dissatisfied.
"I am the legitimate grandson of Kudo Suketaka, the lord who developed this region, and I should be the one to inherit Ito, the center of that territory. I cannot tolerate that a mere stepson of a second wife, who has no blood relation to me, should take the name Ito and hold a larger territory than I do."
That was his reasoning.
Whether he knew of Kawazu Sukechika's dissatisfaction or not, Kudo Suketaka left a will before he died, telling his grandson, Kawazu Sukechika,
"When Suketsugu dies, take in his son, Suketsune, and raise him."
He was telling the two families to get along. It is quite carefree of him to have created the cause of the conflict himself and then said such a thing.
Well, after that, Ito Suketsugu died of illness. Kawazu Sukechika immediately began to take action to settle his long-standing grudge. He rode into the land of Ito and declared,
"I will govern Ito as the guardian of Ito Suketsune."
He then began to call himself "Ito Sukechika." This is the same Ito Sukechika who appeared earlier and murdered Chizumaru, Yoritomo's first child.
At first, Ito Sukechika raised Suketsune according to his grandfather's will. When Suketsune turned 13, he even had him undergo his coming-of-age ceremony under the name "Kudo Suketsune" and married him to his own daughter, Mangou, so it is fair to say he kept up appearances well enough.
However, Sukechika eventually tried to conveniently drive Suketsune out and usurp the land of Ito.
Sukechika told Suketsune,
"To commemorate your coming-of-age, I will introduce you to Taira no Shigemori."
He took him to the capital, and then, surprisingly, suggested to Suketsune,
"Since you are here, why don't you gain some experience working in the capital?"
In other words, he abandoned him there and returned to Ito by himself. He had successfully driven Suketsune out.
Upon returning to Izu, Ito Sukechika had his own son take the name Kawazu Sukeyasu (1146–1176) and govern the Kawazu territory. Now, he and his descendants would govern both Ito and Kawazu entirely.
Thus, the internal conflict within the Kudo family gradually became more serious.