Kayain (a residence) (高陽院 (邸宅))

Kayain was one of the Satodairi (temporary imperial residence) in Heian-kyo. It was a huge residence located west of Nishinotoin Oji street and north of Oinomikado Oji street, the size was approx. 218m from north to south (later it was enlarged to approx. 436m).

It is said that originally it was the residence of Imperial Prince Kaya of Emperor Kanmu, though the owner changed many times and finally in the early 11th century, Sessho (a regent) FUJIWARA no Yorimichi loved the place very much, owned, enlarged the premises to double in length to approx. 436m and constructed a gorgeous Shinden-zukuri (architecture representative of a nobleman's residence during the Heian period) buildings. Yorimichi managed a longtime rule of the government based in this Kayain.. When he retired to Uji Byodo-in Temple, although the ownership was transferred to the heads of the line of regents and advisers, the residence was provided as a satodairi for the line of emperors.
Five generations of emperors after Emperor Goreizei resided in the palace,
The reason why nyoingo (a title of respect given to close female relatives of the Emperor or a woman of comparable standing) Kayanoin was bestowed on FUJIWARA no Taishi (Yasuko) (a great-great-granddaughter of Yorimichi and a daughter of Kanpaku (chief adviser to the Emperor), FUJIWARA no Tadazane) is derived from the fact that she lived in this palace.

Even after a number of fires, the residence was reconstructed and the Retired Emperor Gotoba was also based in this palace and administered Insei (Cloistered government.)
The venue where the conspiracy to ruin the Kamakura bakufu (Japanese feudal government headed by a shogun) that led to the Jokyu War occurred in this Kayain. After the war in 1223, the Kayain was set fire and lost, however, it was never rebuilt again, in fear of the bakufu.