Doshin Bansho Guardhouse of the Edo Castle

Doshin Bansho is one of three guardhouses that survives from the Edo Castle, from Tokugawa Shogunate (1603-1867). It was manned by low-ranking samurai known as doshin, or constables, hence its name. Their job was to check visitors to the castle, and to keep watch over the retinues of the feudal lords as they waited for their masters to return from inside the honmaru complex.
It is located near Ote-mon Gate on the site of what is now the Tokyo Imperial Palace.