平ひら山やま城じろalso: ひらさんじょうひらやまじろMeanings1nounhill castle in the plains; flatland-mountain castleA Japanese castle built on a hill or low mountain within a plain, combining features of flatland and mountain castles. Contrasts with 平城 (ひらじろ, flatland castle) and 山城 (やまじろ, mountain castle).See also: 平城 (ひらじろ) · 山城 (やまじろ)姫ひめ路じ城じょうは平ひら山やま城じろ