Ryuoo Ski Park Mountain

The mountain

竜王山 (Ryūō-zan) 1,933 m

Above it

焼額山 (Yakebitai-yama) 2,010 m

Landform

Ryūō-zan is a peak in the Shiga Kogen volcanic group. The Geological Survey of Japan catalogues that group as one composite andesite volcano group, active between about 2.7 and 0.7 million years ago. The catalogue lists Yakebitai among its summits and places the group's reference point on Yakebitai-yama, 2 km south-east of the top of the lifts; it does not list Ryūō-zan as a volcano of its own. The ski area occupies the west-north-west flank of this north-western corner of the group. The lifts end on the summit ground: the 1,933 m top stands 130 m east of the highest run, with no dip between them. A 1,855 m col separates that top from Yakebitai-yama. The 1,900 m triangulation point 0.9 km to the south-west carries the name 竜王山 on the national topographic map, and the mountain databases call that point 小竜王山.

Rock

From the top of the lifts down to about 1,200 m, the national geological map returns one unit the whole way: andesite and basaltic andesite lava with pyroclastic rock, dated to the late Pleistocene. That is the body of the volcano, and it covers the upper part of the lift-served band, which is why the face measures as one broad west-north-west slope. Below about 1,000 m the map changes to fan and talus deposits of the latest Pleistocene and Holocene, loose material shed off the mountain onto the valley floor, so the lifts at the base sit on debris from the mountain. Two GSJ products give different ages for this ground: the seamless map dates the lava to the late Pleistocene, and the volcano catalogue puts the whole Shiga Kogen group at 2.7 to 0.7 million years ago. Both figures come from the national survey, and the sources read do not explain the difference.

From published sources, checked by hand · 2026-10-15

That ground is outside the ski area. It is not patrolled.