This structure was a passage that connected the outer (administrative) world and the Oku or the inner (living) quarters known as Ouchibara. It connected the Nanden and the second floor of the Kugani Udun, built with a room called Suzubiki. If some business required attention, a bell in the Suzubiki room would be rung, and an official would come to answer.
This building was destroyed in the fire.