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Joshin’etsukogen NP, Niigata / Nagano
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At 2,145m, Naeba’s summit spreads into a lava-built plateau rather than a sharp peak. Its roughly 700-hectare high moor is dotted with thousands of small ponds.
During an 1811 ascent, Echigo writer Suzuki Bokushi described summit “seedling fields” where grass looked planted, frogs and locusts lived, and water reportedly never dried—the landscape behind 苗場’s name.
These aren’t tiny crater lakes: rainwater slowly fills spaces in accumulated peat. Peat adds only about 1mm a year, and sediment evidence suggests the ponds began forming roughly 7,000 years ago.
Just 85cm of summit peat preserves 12 visible ash layers. Researchers matched several to Myoko and Kusatsu-Shirane eruptions; another layer mixes distant Kikai-Akahoya ash with Myoko-Akakura ash.
Beneath the summit’s Ime Jinja shrine grows Hikarigoke, or “luminous moss.” It doesn’t make its own light: tiny rounded cells reflect faint light in a green-gold shimmer.
At Ime Jinja’s Mitsumata village shrine, a harvest festival is held each July 12. Bearers in old-fashioned aristocratic dress parade a portable shrine through the village.
Shugendō ascetics still climb to Ime Jinja, the summit’s main shrine, in early summer to pray for hikers’ safety and purify the mountain before climbing season.
The bog’s plant life includes sundew, a tiny carnivore whose sticky leaf hairs trap insects. This helps it get nutrients in the acidic, nutrient-poor peat.
A 2012 resurvey still found a narrow, bare trampling scar in Naeba’s peat plots, 7 years after the trail was changed to keep feet off the damaged ground. Mountain-bog plants can take decades to recover.
