revised on 9th January, 2020.
Unfortunately you are not able to see the moss cave due to the rain fall in 2014. The observation stage was devastated and closed.
Koke-no-domon(苔の洞門) is located in the southward of Lake Shikotsu-ko. It has been familiar for people to come because of constructing a road from Lake Shikotsuko to Lake Doyako in 1960s. “Koke” means moss plant and “Domon” means tunnel, but no ceiling. Koke-no-domon is a dried-up mountain stream which was formed with ignimbrite by eruption of Mt.Tarumae in 1739.
Koke-no-domon has two parts. One is Daiichi Domon – No.1 Domon – 420 meters long and Another is Daini Domon – No2 Domon, 600 merters long. Both Domon’s walls are covered with moss plants. This is a natural mysterious corridor colored by moss’s green.
Visitors can go to the observation stage at the entrance of Daiichi Domon and prohibited to enter the tunnel over the stage because of collapse. There is a visitor house and parking. When you go to Lake Shikotsu-ko, you should go there just 15 min by car from Shikotsu-ko visitor center. This is worth visiting.
Take a bus(Chitose-Niseko Line) at Chitose station to Kokenodomon. 2 buses a day and only in summer.