- Matsumoto Castle is a "castle of plain" located in Matsumoto city and originates from Fukashi Castle built in 1504. Later Ogasawara Family extended it and renamed "Matsumoto Castle". Ishikawa Kazumasa and his son, Yasunaga, completed it. The actual donjon, which is well known by a varied construction and a skillful design, is composed of a 5-staged 6-storied main donjon at center and small adjacent towers such as "Inui" mini donjon and moon watching tower.
- Inui (north-west) Mini Donjon owes this name to the location in the north-west of the main donjon. It has 3 stages and 4 floors, and is linked to the main by a "bridge tower". The particularity of Inui Donjon's building plan is an use of log columns.
- The donjon of Matsumoto castle has, in the north, Inui mini donjon which is linked by a "bridge tower" and in the east, Tatsumi (sud-east) ancillary tower and Moon watching tower. We call it together "joint composite tower building". The stone wall uses unprocessed rocks and the outer wall is made of white plaster, equipped with beneath looking boards, loopholes and machicolations.
- Moon watching tower as well as Tatsumi (sud-east) ancillary tower were constructed by Matsudaira family about 35 years later than the main donjon. This tower is open to 3 directions, i.e. north, east and south and equipped with sliding doors (Maira-do), the brackets supporting a red painted air corridor outside.