The characteristics of the main floor plan are that the floor is divided in half between doma (dirt floor area) and zashiki (Japanese style tatami rooms) by ipponbiki-amado (wooden sliding storm doors mounted on one straight track) and, inside the zashiki area, there are chodaigamae (a built-in ornamental doorway found in the raised area of a formal style reception suite), shikii (threshold) and kamoi (door lintel) of each majikiri (partition) between zashiki are designed to stop the sliding door at the specific point.
平面形式は土間と座敷が折半、同境に一本引き雨戸があり、座敷内部では、帳台構え、各間仕切の敷居・鴨居が突き止めであることなどが一階平面の特質である。