The is the ruins of a Buddhist nunnery located in the city of Ichihara, Chiba, Japan, which was part of the provincial temple complex ("kokubunji") of former Kazusa Province.The temple ruins were designated a National Historic Site in 1983, with the area under protection expanded in 1985.
The Shoku Nihongi records that in 741, as the country recovered from a major smallpox epidemic, Emperor Shà Âmu ordered that a monastery and nunnery be established in every province, the .
The Kazusa Kokubun-niji was located on the northern bank of the Yà Ârà  River, in an area with a high concentration of kofun and ancient sites, and is separated from the Kazusa Kokubun-ji, which was located a short distance to the southwest, by a shallow valley. After several archaeological excavations starting in 1948, the layout of the temple was confirmed. The total area of the temple complex was north-to-south by east-to-west, for a total area of , making it the largest nunnery in the kokubunji system yet discovered. The central enclosure, containing the main structures of the nunnery, measured north-to-south by east-to-west. The foundation stones for the South Gate, Middle Gate, Kondà Â, Lecture Hall, Cloisters, bell tower, sutra tower, and the residential building for the nuns have been found. In addition, there are traces of a metal workshop, medicinal plants garden and infirmary. In 1996 the Middle Gate and part of the Cloister were restored, and a museum (the was built on the site to display various artifacts that have been unearthed. It also contains a large diorama showing how the temple complex may originally have looked. The site is a ten-minute walk from the Ichihara City Hall bus stop on the Kominato Railway Bus from Goi Station on the JR East Uchibo Line.