This northernmost cave in Japan lies on Karst, that is a topography formed from the dissolution of soluble rocks such as limestone. It is characterized by underground drainage systems with sinkholes and caves. Limestone around Nakatonbetsu area has been formed by piling up of shells, that is quite rare example in the world.
Admission is free. In winter entering is prohibited in principle. IOW, to trek this site alone without experienced guide is far from recommended. But “Soya Nature School” gives Snow trekking & Cave questing tour (Sorry, written in Japanese Only) in midwinter at a small fee for what they are offering.
You can see a 500 years old quercus crispula tree at the 4th entrance of the cave. This big tree looks overwhelming…
In winter, “Hyoujun-Ice Bamboo” that is created slowly by piled (then freezed) droplets over time in sub-zero temperatute in the cave can be seen by joining above-mentioned tour.
Snow trekking tour starts like this…
In the cave, tour-guide explains you the details and how to move forward into the deep.
After spending time in the cave, guide serves you a cup of tea and local cookie. The tea contains north thistle honey produced in Nakatonbetsu town. This “Real” honey was so delicious enought to cure the fatigue.