What is "kuruwa"

is a Japanese term that refers to the walls of a Japanese castle, and the regions bounded by the arrangement of those walls. The term may also be written as 郭, and the term is also used for castles built after the Edo period. The kuruwa serves as a defensive territory, provides space for additional castle facilities, and contains the living quarters for common soldiers, making it an important fixture of all Japanese castles. Most castles built during the middle ages contain many kuruwa of small area, while those built during or after the early modern period often contain a lesser number of kuruwa of larger area. The western equivalent is the motte-and-bailey.