Nijo Jinya House, just south of Nijo-jo Castle, is a mansion that was owned by a rich merchant during the 17th century. It was an inn for high-ranking Samurai visiting Kyoto. This inn had a tight security system and many clever tricks to protect its guest. For example, there are hidden staircases and secret hallways. There are also small secret rooms where guards could hide and watch the visitors. You can study the security tricks of 300 years ago in Japan.