Minowa Castle Ruins, Takasaki.

“Minowa Castle (Minowa-jō) was a ‘hirayama’-style castle located in the Misato neighborhood of the city of Takasaki, Gunma Prefecture, Japan. The ruins have been protected by the central government as a National Historic Site since 1987.”

NB. A hirayama castle is one “built on a low mountain or hill on a plain. The term literally translates to ‘flatland mountain castle’.”