Although the structural style of betsuma is much the same as that of omoya (main building), because kiwari (a system for measuring out the wooden component to be used in architecture or statuary) which is in a direct proportional relationship with the size of each component is small, and because there are the shoin-like (reception room) marks in hashirama (bay, space or distance between two pillars) at the south end of the main floor, it is considered that the eight-tatami room in the south side of the betsuma was probably built in the shoin style.
別間の構造形式は、主屋と大差はないが、各部材の大きさの比例関係である木割りの小さいことと、一階南端柱間には書院のような痕跡のあることから、南八畳間の座敷はあるいは書院形式のものではなかったかと思われる。