Introduction to Ninomaru Palace: Nino palace circle is a building in the center of Ninomaru. It is surrounded by Tsukiji walls, and the Karamon gate on the south side is the entrance. When entering the Ninomaru Palace, there are six buildings connected by corridors, namely the Samurai Room, the Shidai Room, the Great Hall, the Cycad Room, the Black Academy, and the White Academy.