Koka Ninja House, House museum in Kōka, Japan

Koka Ninja House is a wooden residence filled with hidden doors, secret passages, and concealed chambers throughout. The rooms are arranged in a maze-like pattern to allow quick escape and offer protection from intruders.

The residence was built in the late 1600s as a home for Mochizuki Izumonokami, a leader of the Koka Ninja Clan. Its architecture reflects the practical needs that ninja faced during that era.

The house reveals how ninja organized daily routines between martial practice and family life. Visitors can observe rooms designed for both purposes and see the tools used for preparation.

The residence can be explored by most visitors but requires care when navigating through narrow passages and uneven floors. Wearing comfortable shoes and moving slowly helps you avoid missing the hidden details throughout.

The house displays a photo of Harrison Ford relaxing in front of a kettle during a private visit, along with a signature he wrote there. The Mochizuki family crest, a nine-star circle, appears on roof tiles throughout the building.