S P O T ／ SPOT-346

Osawa Limestone Cave (Osawa Shonyudo)

大沢鍾乳洞おおさわしょうにゅうどう

Osawa Cave is a 145.9-meter-long cave in the mountains near Osawa Pass in Gosen City, Niigata. Unlike most Japanese caves, which form in hard, ancient limestone, this one developed within soft Neogene sandstone (ca. 24-1.8 million years old), a nationally rare occurrence that earned it designation as a city Natural Monument in 1993. The interior has no lighting at all, with narrow, slippery passages, so a flashlight and boots are essential. Stone statues of Inari and Kannon are enshrined deep inside, and bats inhabit the cool, dark space. Admission is free and the cave is open year-round, though heavy snow may block entry in winter, offering a raw, unimproved caving experience far removed from a developed show cave.