Rikyu (an Imperial villa) (離宮)
Rikyu is an Imperial villa which is separate from the Imperial Palace or Palace.
Generally Rikyu is built on different land from the Imperial Palace of the Royal Family and the Imperial Family. A good example of this is after Crown Prince becomes an adult and is married, he will have separate palace from the Emperor and the Empress, in this case the palace will be called Rikyu. Some Rikyu are built as a summer or winter holiday villa or as a place to stay for recuperation. In Japan a villa with a certain size of land including the villa itself, is called Rikyu, and the one of smaller size are called goyotei (Imperial villa). Before the Meiji period, there were Rikyu built as a villa for a retired emperor and cloistered emperor for after their retirement, which were called 'Goin,' and there were exclusive officials to look after these places. There were many posthumous titles for emperors during the Heian period which came from the name of the goin.
The list of the Rikyu
Katsura Imperial Villa : Kyoto City, Kyoto Prefecture
Shugakuin Imperial Villa : Kyoto City, Kyoto Prefecture
The list of the Rikyu granted by the Imperial Palace
Akasaka Palace (current State Guest House): Minato Ward, Tokyo
Kasumigaseki Imperial Villa (current south area of Kokkai mae niwa (garden)): Chiyoda Ward, Tokyo
Shiba Imperial Villa (it is currently known as the former Shiba Imperial Garden): Minato Ward, Tokyo
Nagoya Imperial Villa (Nagoya-jo Castle): Nagoya City, Aichi Prefecture
Nijo Imperial Villa (Nijo-jo Castle): Kyoto City, Kyoto Prefecture
Hakone Imperial Villa (current Kanagawa Prefecture Hakone Royal Garden): Hakone-cho, Kanagawa Prefecture
Hama Imperial Villa (current Hama Royal Garden): Chuo Ward, Tokyo
Muko Imperial Villa (current Suma Rikyu Park): Kobe City, Hyogo Prefecture