The house is constructed entirely without nails in many sections, relying instead on intricate interlocking wood joinery.
A 'nuke-ishi' (escape stone) is hidden near the entrance, allowing occupants to exit unseen during an emergency.
The structure includes a 'nando-kakushi' (secret room) tucked between the ceiling and the roof, designed for silent observation.
Stairs are strategically designed to be steep and narrow, creating a defensive bottleneck against intruders.
The family living here were not just warriors but also practiced traditional medicine, which was a common cover for ninja clans.
The house was moved to its current site from its original location nearby to ensure its preservation for the public.
The Koka Ninja House is the only remaining authentic residence of a Koga ninja family in Japan, dating back to the late 17th century. The building was constructed by the Mochizuki family, who served the Koga clan, and features a deceptively simple exterior designed to blend into the rural landscape. Internally, the residence incorporates numerous defensive mechanisms, including hidden trapdoors, secret revolving walls, and concealed escape routes. Visitors can explore the multi-story structure to see how space was utilized for both domestic living and clandestine combat readiness. The site retains its original architectural integrity, showcasing traditional Edo-period carpentry and stealth-focused design. It functions as a living museum, emphasizing the history of the Koga ninjas rather than modern theatrical representations.
The internal central corridor where the interlocking defensive mechanisms and secret doors are clearly visible.
Attempt to locate the hidden revolving wall panel on your own before asking the staff for a demonstration.
Wear socks, as you will be required to remove your shoes to walk on the original wooden floorboards.
Look for the small lookout windows disguised as decorative architectural elements.
Do not mistake the modern tourist center building for the original residence; the historical house is the structure behind the reception area.
Typically closed during the year-end and New Year holidays.
Remove shoes at the entrance; avoid touching the fragile, century-old wood structures; maintain a quiet demeanor.
