Mount Hakone (箱根山, Hakoneyama), with its highest peak Mount Kami (1,438 meters), is a complex volcano in Kanagawa Prefecture, Japan that is truncated by two overlapping calderas, the largest of which is 10 × 11 km wide.

Dome growth occurred progressively to the south, and the largest and youngest of them, Mount Kami, forms the high point of Hakone.

It produced a pyroclastic flow and a lava dome in the explosion crater, although phreatic eruptions took place as recently as the 12–13th centuries AD.

[1] According to the nearby Hakone Shrine, the Komagatake peak has been the object of religious veneration since ancient times.

Later about 3,000 years ago, the phreatic eruption on the northwest side of Mount Kami caused landslides, creating the Owakudani and, in the huge caldera, the Sengokuhara and Lake Ashi.