Passing through the Eastern Main Gate (Higashi Ote Mon), there is a long (19.6 m) and narrow building with some mannequins (posing as guards) sitting or standing upright. Called Bansho in Japanese, the building functioned as a guardhouse where stationed staff regulated and welcomed the visitors to the castle.
The guards were called Nijo Zaiban or "Nijo Guards," and dispatched from Edo (presently Tokyo). A hundred of them in total were assigned for the job by splitting into two group units each of which consisted of 50. The units worked on yearly shifts: one replacing another every April.
Once there were many such guard stations throughout the castle, but the one near the Eastern Main Gate is the only one remaining today. For its rarity, the house serves as an important historical reference.