Kumamoto Castle is one of the three great castles in Japan.  It has unique stone walls, “Musha-gaeshi.”  The bottom of a Musha-gaeshi looks easy to climb, but it becomes too steep to climb when you go up.  Even skilled ninjas could not climb them, so they are called “Musha-gaeshi.”

    These walls were built by a skilled group called Taneyama-ishiku.  They are known for creating structures like the Tsujun Bridge in Kumamoto and the Old Nijubashi Bridge in Tokyo.