, also romanized as Kō-ō, was a Japanese era name (年号, nengō, lit. year name) of the Northern Court during the Era of Northern and Southern Courts after Kakei and before Meitoku. This period spanned the years from February 1389 to March 1390. The emperor in Kyoto was The Southern Court rival in Yoshino during this time-frame was .
Nanboku-chō overview
thumb|140px|The Imperial seats during the Nanboku-chō period were in relatively close proximity, but geographically distinct. They were conventionally identified as:
This illegitimate was established in Kyoto by Ashikaga Takauji in 1336.
Change of era
- 1389, also called : The new era name was created to mark an event or series of events. The previous era ended and the new one commenced in Kakei 3.
In this time frame, Genchū (1384–1393) was the Southern Court equivalent nengō.
Events of the Kōō era
- 1389 (Kōō 1): Dissension continues in Toki family in Mino.
- 1389 (Kōō 1): Yoshimitsu pacifies Kyūshū and distributes lands; Yoshimitsu opposed by Kamakura kanrei Ashikaga Ujimitsu.
- 1390 (Kōō 2): Kusunoki defeated; Yamana Ujikiyo chastises Tokinaga.