Koke no Domon is a remarkable natural formation near Lake Shikotsu in Chitose, Hokkaido, where moss-covered rock walls create an enchanting corridor through the forest. The landscape was formed from cracks in lava that flowed during an eruption of Mount Tarumae. Over time, flowing water from streams and other natural forces eroded the volcanic rock, creating the distinctive passageway seen today.
Approximately 30 species of moss grow densely across the rock walls, giving the gorge an intensely green and otherworldly appearance. The combination of volcanic rock, moss, forest, and filtered light creates one of the most atmospheric natural landscapes around Lake Shikotsu.
The formation of Koke no Domon is closely connected to the volcanic history of the Lake Shikotsu region. Lava released by the eruption of Mount Tarumae cooled and hardened, leaving fractures within the rock. Stream water gradually eroded these weaknesses over many years, eventually producing a long, corridor-like formation.
The humid environment created within the narrow passage provides ideal conditions for moss. The vegetation spreads across the rock surfaces, covering the volcanic walls in layers of green and giving the site its name, which literally means “Moss Cave Passage.”
The main attraction is the extraordinary moss scenery. Delicate mosses cling to the rock walls and surfaces, creating a lush natural texture that changes subtly with the light and moisture.
The formation measures approximately 10 meters in height and extends for about 420 meters. Its narrow, winding character gives the landscape the feeling of a natural gallery carved into the volcanic terrain.
In June 2001, part of the rock formation collapsed, making it impossible for visitors to enter the interior of the gorge. For safety and conservation reasons, visitors now view Koke no Domon from an observation platform near the entrance.
Although the interior passage is no longer accessible, the viewing area provides an opportunity to appreciate the distinctive moss-covered walls while protecting this fragile natural environment. The surrounding forest also adds to the sense of seclusion and tranquility.
Koke no Domon is generally open to visitors from early June through late October, when the surrounding landscape is accessible and the moss-covered gorge can be viewed in its seasonal setting.
The greenery of the forest and moss makes the site particularly appealing during the warmer months. Because the landscape is shaped by natural conditions, weather and moisture can influence its appearance from day to day.
Koke no Domon offers a different perspective on the volcanic landscapes of the Lake Shikotsu area. Rather than a broad mountain panorama, it is a place of intimate scenery, where ancient volcanic rock and delicate moss coexist in a narrow natural corridor.
Combined with the forests, mountains, and exceptionally clear waters of Lake Shikotsu, the moss gorge provides an atmospheric glimpse into the natural forces that have shaped southern Hokkaido. Its unusual geology and lush vegetation make it a memorable stop for travelers interested in the quieter side of the region’s natural beauty.
9:00-17:00, admission until 16:00
Open to the public early June to late October
50 min. by car from Chitose Station [35km].