Stories of the Japanese 01418 [Nobuhiro's Crossing] The Birth of Kakizaki Nobuhiro

Takeda Nobuhiro began to be held in high regard for his active role in suppressing the rebellion. Episodes such as his noble birth as a member of the Wakasa Takeda clan or his status as a guest general under Ando Masasue may have been fabricated later.
Come to think of it, regarding the three-constable system, some documents record that the Kaminokuni constable was Takeda Nobuhiro. It is hard to believe that Takeda Nobuhiro held such a high position before the Koshamain Rebellion; in reality, it is likely that Kakizaki Suehige was the constable, and Takeda Nobuhiro held a position akin to a deputy general assisting him.
Regardless, Takeda Nobuhiro used this opportunity to rise to the position of hegemon of Ezo Island.
First, in August of the first year of Choroku (1457), Kakizaki Suehige, who was troubled by the lack of an heir, adopted the daughter of Ando Masasue, married her to Takeda Nobuhiro, and decided to have him succeed as the head of the Kakizaki family. Perhaps he thought that if he were to hand over the family headship to someone else, it should be to a hero recognized by all. With this, Takeda Nobuhiro became a member of a prestigious family possessing the lineage of the Ando, Kakizaki, and Takeda houses, and from this point on, he began calling himself "Kakizaki Nobuhiro."
Also, around this time, Nobuhiro began calling himself "Wakasa-no-kami Seigan," positioning himself as a descendant of the Wakasa Takeda clan.
The Kakizaki family's base was Hanazawa-tate, but in August of the first year of Choroku (1457), Nobuhiro built Suzaki-tate (in Kaminokuni, Hokkaido) nearby and established it as his base. Suzaki-tate then became an entity that stood above the three constables of Matsumae, Kaminokuni, and Shimonokuni. He may have built a new fort to declare that he was assuming a more powerful position than the previous Kaminokuni constables.
In April of the second year of Choroku (1458), Nobuhiro dispatched Sasaki Shigetsuna to suppress the remnants of the Koshamain forces. The details are unclear, and it is not well understood who struck first or the scale of the battle.
Then, in the following May, Nobuhiro gathered the chieftains of the eastern and western Ainu and made them swear allegiance to him. While the previous stance had been that the Wajin and Ainu traded on equal footing, from this point on, the Ainu became subordinate to Nobuhiro's regime. It was the moment the Ainu officially came under Wajin rule for the first time.
After that, the descendants of Kakizaki Nobuhiro ruled Ezo Island for generations, and upon entering the Edo period, the Kakizaki clan changed their name to the "Matsumae clan." The Kakizaki clan, now the Matsumae clan, would go on to prosper through trade (though sometimes exploitation) with the Ainu.