Stories of the Japanese 01138 [Late Northern and Southern Courts Period] The Arrival of the First Kanrei, Shiba Yoshimasa

I have explained the suppression of the Hatakeyama clan, which took place from the third to the ninth month of the 17th year of Shohei/2nd year of Koan (1362), all at once, but I need to go back in time a little to record the events that occurred in parallel with it.
The shogunate, having lost Kyoto four times, was finally able to return Emperor Go-Kogon to the capital and was catching its breath. Nevertheless, with the continued betrayal of high-ranking officials such as Shiba Takatsune, Yamana Tokiuji, Niki Yoshinaga, Hosokawa Kiyouji, and Hatakeyama Kunikiyo, the shogunate was naturally feeling a sense of crisis and was considering whether it could somehow bring those who had defected to the enemy back to the shogunate's side.
Yoshiakira set his sights on Shiba Takatsune in particular among the traitors and tried to win him over. Shiba Takatsune had betrayed the shogunate in the first month of the 6th year of Shohei/2nd year of Kanno (1351) during the Third Battle of Kyoto, but he had not fought any notable battles since then and had been holed up, so Yoshiakira likely thought that if he negotiated, Takatsune would return to the shogunate.
Yoshiakira boldly nominated Shiba Ujiyori as the successor to the departed steward, Hosokawa Kiyouji. Since Shiba Ujiyori was Takatsune's third son and also the son-in-law of Sasaki Doyo, it is thought that there was also a recommendation from Doyo.
However, Shiba Takatsune insisted,
"Our Shiba family is of the Ashikaga clan. It is a disgrace to take the position of steward."
and did not allow his son to take the position of steward. Indeed, the Shiba family is originally of a lineage that could even aim for the position of shogun, so the position of steward might have been beneath them, but I do not think that was the only reason for the refusal. He probably just wanted to refuse by making up any excuse.
Yoshiakira still patiently continued to try to please Shiba Takatsune. This time, he said,
"Then you should appoint the son you are particularly fond of as steward,"
and conveyed that he wanted to make his fourth son, Shiba Yoshimasa (1350–1410), who was only 13 years old, the steward. He was still too young to work as a steward, but Yoshiakira said,
"While he is young, his father Takatsune can serve as his guardian,"
and actually offered the traitor Shiba Takatsune the number two position in the shogunate. It was an incredibly generous offer.
Takatsune, as expected, agreed to this, and on the 23rd day of the seventh month of the 17th year of Shohei/2nd year of Koan (1362), Shiba Yoshimasa took the seat of steward. When his older brother Ujiyori learned of this, he resented his father, secretly became a monk, and disappeared. Even the year of his death is not clear.
Shiba Yoshimasa, who appeared on the political stage by chance, had the real power held by his father Takatsune at the time he became steward, but after Takatsune's death, he would reign as the supreme authority in shogunate politics.
Incidentally, some time after this, the authority of the steward came to extend to the entire administration. It is from around this time that what had been called "steward" began to be called "Kanrei," and Shiba Yoshimasa is considered the first Kanrei of the Muromachi Shogunate.