Stories of the Japanese 00585 [Early Kamakura Period] The Downfall of Tsuchimikado Michichika

Around the same time that Kajiwara Kagetoki fell from power in Kamakura, Tsuchimikado Michichika, who had gained immense authority within the Imperial Court by building connections with the Shogunate, also fell from power due to an unexpected cause.
According to the historical record "Gukansho" written by Jien, the incident began in June of the first year of Shoji (1199), when rumors spread that Zaishi, an adopted daughter whom Tsuchimikado Michichika had introduced to Emperor Go-Toba, was having an illicit affair with Michichika. Since Zaishi was his wife's daughter from a previous marriage, they were not blood relatives, but if true, it would have been a scandalous act of adultery.
This rumor spread rapidly, and Retired Emperor Go-Toba began to distance himself from Zaishi and Emperor Tsuchimikado, whom she had borne, choosing instead to favor only his consort, Fujiwara no Shigeko (1182–1264).
This is very similar to the case where Retired Emperor Toba suspected his son, Retired Emperor Sutoku, of not being his own child and grew to dislike him, shifting his favor to Bifukumon-in Tokushi. Perhaps in this instance, Retired Emperor Go-Toba suspected his son, Emperor Tsuchimikado, of not being his own and shifted his favor to Fujiwara no Shigeko.
However, since this scandal involving Zaishi does not appear in any literature other than the "Gukansho," some are of the opinion that it may have been a malicious rumor recorded by Jien.
Fujiwara no Shigeko had given birth to Retired Emperor Go-Toba's son, Imperial Prince Morisada (later Emperor Juntoku: 1197–1242), two years before the scandal involving Zaishi occurred. Once negative rumors began to circulate about the Tsuchimikado Michichika-Zaishi-Emperor Tsuchimikado line, the presence of Imperial Prince Morisada naturally grew as a successor to the throne.
On February 9th of the second year of Shoji (1200), Michichika wrote in his diary:
"At this point, my power is no longer sufficient."
He lamented that despite his best efforts to support Emperor Tsuchimikado and Zaishi, things were not going well.
As Michichika had feared, on April 15th, Imperial Prince Morisada became the Crown Prince, and Emperor Tsuchimikado lost his standing.
Then, on October 21st of the second year of Kennin (1202), Michichika passed away from a sudden illness while in despair, and Zaishi lost her protector. Consequently, Kujo Kanezane, whom Michichika had ousted during the political upheaval of the seventh year of Kenkyu, saw an unexpected restoration of his power.
Reflecting on it, Retired Emperor Go-Toba's favor had shifted from Kujo Ninshi to Tsuchimikado Zaishi, leading to Ninshi being driven out of the palace. Now, the favor had shifted from Tsuchimikado Zaishi to Fujiwara no Shigeko, and Zaishi had fallen from power. Though it is the way of the world, the power struggles within the palace were truly fierce.
Incidentally, Zaishi, who lived in despair, remarkably lived until the first year of Shoka (1257) and died at the age of 87. That is a surprising longevity for the time.