Also read hirasanjiro. Lit. "flatland mountain castle." A castle built on a low mountain, defined as 20 to 100 m high, that rises up from a plain and extends down to the plain or flatlands at the foot of the mountain. The defensive installations were built on the mountain top while residential quarters were built in the foothills, thereby combining the strongpoints of both mountain castles *yamajiro 山城 and flatland castles *hirajiro 平城. While the location of this type of castle reflects strategic concerns to some extent, political and economic considerations were also central. Castles built on the shores of bodies of water and river banks point to the importance of water and transportation as well. Representative examples include Hikone-jō 彦根城 in Shiga Prefecture, Kumamoto-jō 熊本城 in Kumamoto Prefecture, and Maruoka-jō 丸岡城 in Fukui Prefecture. It is one of the three types of castles classified by Edo military scholars according to geographical topography.