The stairs on the left will take you to the "Honmaru." According to records that were discovered, the size of the area inside this inner circle of defense was approximately 2,715 square meters. Tall stone foundations and walls were built around the circumference, and 79 windows made into various shapes such as circles, triangles, and squares were put into the walls to be used as way to attack enemies with guns and bows and arrows. At the entrance to the Honmaru is a gate called "Honmaru-ichi-no-mon." If you go through Honmaru-ichi-no-mon Gate, you will see a square space with an area of 5.5 square meters that is enclosed by a low stone foundation. The remaining stones that acted as a foundation to the gate as well as the drainage ditch were renovated in 1857.
Adjacent to the right side of the gate inside of Honmaru were long, thin buildings, and in the very back of the left side was the castle keep. Also included in this area was a 16.5 square meter warehouse that stored weapons such as bullets for firearms.