Ryugu Sea Cave: Shimoda's heart-shaped skylight
A sea-eroded cave whose collapsed roof forms a skylight about 50 metres across, heart-shaped when seen from the path above.
- Skylight
- about 50 m across
- Rim walk
- 15–20 min
On the coast at Toji, south of Shimoda, a short tunnel in the cliff opens into the Ryugu Sea Cave (Ryugukutsu): a cavern carved by the waves along weaker layers and faults in the rock, whose roof later collapsed. The result is a skylight roughly 50 metres across, one of the largest in Izu, with a little beach and the sea rushing in at the bottom.
Two ways to see it
Walk through the tunnel to stand inside the cave and look up at the sky framed by the rock walls. Then take the footpath that climbs around the rim: from above, the opening has the shape of a heart, which has made it a favourite with couples and photographers. The loop takes 15 to 20 minutes.
Geology
The cliffs are layers of pale volcanic sediment laid down when Izu was still a group of undersea volcanoes drifting north on the Philippine Sea plate. You can see the layers clearly from the rim; the cave is part of the Izu Peninsula Geopark.
Practical notes
The cave has a small car park. Next to it is the natural sand slope of Toji, where children slide down on sleds. From Shimoda, local buses towards Toji stop nearby.
