Kuruwa

Kuruwa (曲輪, くるわ) 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 maru (丸) 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.

Arrangement

The shape and structure of a castle were important factors in determining the victor of castle sieges, and the castle layout, or nawabari (縄張) was arranged with the intention of giving the defender an insurmountable advantage. The kuruwa regions were planned for after the basic layout of the castle grounds was decided. The three basic kuruwa regions are the honmaru (本丸); the core of the castle, and the ninomaru (二の丸, lit. "second circle") and sannomaru (三の丸, lit. "third circle"), which serve as auxiliary areas.