Welcome to Shiroyama Park, in Takayama, in Gifu Prefecture, Japan. In Japanese it is written 城山公園, and the name means castle mountain. Detailed records of the park's individual corners are modest, so on this walk I'll tell you what is solidly known: how the park began, the ground it sits on, and the remarkable town around it. The park covers 24.3 hectares, about 60 acres, in the mountainous area around the ruins of Takayama Castle. That is a lot of green space for a place that lies a short walk from one of Japan's best-preserved old towns. Takayama sits in the Hida Mountains region, and this hillside is part of its story. So settle in. We'll look at the castle that gave the park its name, the monuments tucked among the trees, and the long, quiet culture that grew up in these mountains.