Komoro Castle

Komoro Castle, known as Kaikoen, served as the seat of regional power in eastern Nagano for over 300 years and is notable as one of Japan's rare 'hole-in-the-ground' castles, built below the level of its surrounding castle town rather than on a hilltop. The park-like grounds retain impressive stone walls and gates dating to the early 1600s, along with cherry trees that make spring visits particularly scenic. The site includes a small zoo, an amusement area for families, and the Choshoji Temple where the literary master Shimazaki Toson once studied. From the castle grounds, visitors can gaze across the Chikuma River valley toward the snow-capped peaks of the Japanese Alps, a view that has inspired artists and poets for centuries.