Koka Ninja House

The Koga-ryu Ninjutsu House is a historic ninja residence that uses the former main family home of Mochizuki Izumo-no-Kami, who served as a leading figure among the 53 Koga ninja families. Located in Koka City, this building was constructed in the Edo period. The presence of the Kuyomon (nine-star crest) on roof tiles and other features suggests the Mochizuki clan once lived here. From the outside, it resembles a thatched-roof farmhouse, but inside it was designed as a defensive residence, complete with a mezzanine level and hidden rooms on the second and third floors to protect its occupants. Everyday tools and household items from the time are displayed, helping visitors imagine life in the era. Admission is required, but you can explore the interior freely, and the many ingenious mechanisms—such as the "donden-gaeshi" rotating wall, trapdoors, and secret passages—are major highlights. Visitors can also dress up in ninja costumes for photos with the house as a backdrop, and try hands-on activities like shuriken throwing. The nearest station is Konan Station on the JR Kusatsu Line, about a 20-minute walk away. By car, it is about 3 minutes from Konan IC on the Shin-Meishin Expressway.