Giso means reporting conclusions about state affairs to the throne after deliberation by Dijokan (Grand Council of State) under the ritsuryo system (a system of centralized government based on the ritsuryo code).
It is an official organization of kuge (court noble).
On October 18, 1185, the Emperor Goshirakawa issued an imperial letter to hunt down and kill MINAMOTO no Yoritomo by the request of MINAMOTO no Yoshitsune, but the fall of Yoshitsune in the next month threw him into situations. Goshirakawa explained to Yoritomo that it was 'the act of evil spirits' (the item of November 15 of "Azuma kagami" [The Mirror of the East], the item of November 26 of "Gyokuyo" [Diary of Kanezane]), but Yoritomo thrusted a demand for the mouseleum hall reform to check dictatorship of the retired emperor. The demand consisted of the removal of 12 'evil subjects trying to disturb the world in agreement with Yukiie and Yoshitsune' such as TAIRA no Chikamune and TAKASHINA no Yasutsune, governmental management by the Imperial Court by 10 giso kugyo (Noble Council) (Kanezane KUJO, Sanesada TOKUDAIJI, Sanefusa SANJO, FUJIWARA no Muneie, Tadachika NAKAYAMA, FUJIWARA no Saneie, MINAMOTO no Michichika, Tsunefusa YOSHIDA, FUJIWARA no Masanaga, and FUJIWARA no Kanemitsu), and the Imperial edict of inspection to Kanezane (the item of December six of "Azuma Kagami" [The Mirror of the East], the item of December 27 of "Gyokuyo" [Diary of Kanezane KUJO]). Iyo Province, the former place of work for Yoshitsune, became the chigyo-koku (provincial fiefdom) for Kanezane, and new chigyo-koku were also given to Sanesada, Muneie, Saneie, Michichika, Masanaga. Yoritomo's expectation on the giso was so high that he wrote in a letter to Giso kugyo dated on April 30, 1186 that 'I especially state that politics of the whole country should be clarified with giso by kugyo', 'even if an imperial order is issued, it should be opposed again and again for the Imperial Court and the world in case of causing disturbances' (the same item of "Azuma Kagami"). However, kugyo who were appointed as giso kugyo had no personal acquaintance with Yoritomo, and Sanesada who approved of the Imperial order to hunt down and kill Yoritomo was included in the member, therefore the members were not necessarily pro-Shogunate forces. When Kanezane received a letter to recommend private inspection fromYoritomo, he said 'like a dream, like an illusion' in surprise (the item of December 27 of "Gyokuyo") and became frightened that he might be suspected of communicating secretly with Kanto (the item of December 28 of "Gyokuyo"). It seemed that the offers to the other kugyo were one-sided and sudden, many of them were perplexed by the fact that they might be on the firing line between Goshirakawa and Yoritomo. Later, most of the members were brought over to Goshirakawa's side as Innocho Betto (chief administrator of the Retired Emperor's Office) and giso stopped functioning.
In the Edo period, giso kugyo attended on the emperor, passed on Imperial orders to kugyo and those in the lower position, and reported the preceedings to the throne. In 1663, it began with the appointment of Yorinari HAMURO, Motoyoshi SONO, Sanetoyo OGIMACHI, and Motokata HIGASHIZONO for the purpose of assisting the young Emperor Reigen. It was abolished due to the Meiji Restoration.