Koka's Ninja House (忍術屋敷, Ninjutsu Yashiki) is close to 300 years old and used to be resided in by ninja. It appears like an ordinary house from the outside; inside however, it is equipped with many ingenious traps and devices, designed to prevent intruders and to provide a means of escape in times of need. Visitors are allowed to explore the house and discover its various trapdoors and secret passages.
Through various exhibits at the mansion, one can also find out about the various techniques for combat that the ninja employed, and their smart use of unique weapons and tools. There is also a shuriken throwing range where visitors can try throwing the weapons at target boards.
The Ninja House is a 20 minute walk south of Konan Station on the JR Kusatsu Line.