The castle towers designated as National Treasures are sometimes referred to as the ‘Kokuho Shijo’ (the 4 castles designated as National Treasures) (as christened by the Tourism Council for the Cities with the National Treasure Castles), whereas the castle towers designated as Important Cultural Properties are sometimes referred to as the ‘8 Jubun Castles’ (the 8 castles designated as Important Cultural Properties).
国宝に指定されている天守は「国宝四城」（国宝城郭都市観光協議会による名称）、国の重要文化財に指定されている天守は「重文八城」と呼ばれることがある。