The 'Mittanseki' tearoom the size of four tatami mats plus one of less than normal size located in the northwestern corner is highly representative example of the shoin style of tearoom and originally stood as a separate building.
北西隅に位置する四畳半台目茶室「密庵席（みったんせき）」は書院風茶室の代表例で、元は独立した建物だったとされる。