【Makuiwa Course】
The Makuiwa Course is a gentle nature trail that starts at the Sun Valley bus stop and ends at the Ishi no Yu parking area. It covers 3.5 kilometers, with an elevation change of 160 meters, and requires approximately 45 minutes to complete.
The highlight of this course is a ridge of andesite cliffs with pillar-shaped rock formations pleating the walls. These craggy shapes are the result of columnar jointing, which can form when especially viscous lava hardens into rock. The lava cools faster on the surface, making it contract unevenly. This uneven contraction creates evenly aligned shearing forces that fracture the rock. The rough cliff face towering above the trail is scenic in any season, but is particularly notable in autumn, when the leaves of the trees that cling to its little outcroppings turn red and gold.
Where the trail runs along a small stream called the Iwakurasawa River, the pleasant sounds of water flowing over the rocks and the occasional small waterfall can be heard. At dusk in summer, hikers might also see a native species of bioluminescent beetle called the Genji firefly (Luciola cruciata) that makes its home at the water’s edge.