Since Azuchi Castle was built by Oda Nobunaga, a tenshu (castle keep) towering at the center of a castle has been the archetypal image of a Japanese castle and a symbol of its authority. However, there are only 12 castles in Japan, including Himeji Castle, where the tenshu remains intact. Himeji Castle has a five-storied dai-tenshu (large castle keep) and three three-storied sho-tenshu (small castle keeps) connected by three watari yagura (roofed passages), and is designated as a National Treasure of Japan.