Koga is a city located in Ibaraki Prefecture, Japan. As of 1 January 2024, the city had an estimated population of 137,512 in 58,276 households and a population density of 1113 persons per km². The pe

Koga Castle was a Japanese castle located in Koga, Ibaraki Prefecture, Japan. During the Muromachi period, Koga was the seat of the Kantō kubō, under the Ashikaga clan. At the end of the Edo period, K