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Oze NP, Fukushima / Gunma / Niigata
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At Ryūgū, a stream slips into the peat and resurfaces about 50 m away, beyond the boardwalk. The name means “Dragon Palace”: an early hut keeper imagined the hole led to the undersea palace.
“Summer Memories” helped make Oze famous in 1949, though composer Yoshinao Nakata hadn’t visited when he wrote it; he first went decades later. Poet Shoko Ema’s inspiration was mizubasho she saw near Oze’s Katashina gateway in 1944.
Ozegahara’s famous mizubasho bloom as the snow retreats, mainly from mid-May to mid-June. The flowers immortalized in “Summer Memories” are really a late-spring sight, not a midsummer one.
At about 1,400 m, Ozegahara is Honshu’s largest mountain marsh—but its peat grows only 0.7–0.8 mm a year. A 1-cm hollow from a footstep can take more than a decade to recover.
Ozegahara’s pools shelter Oze-kohone, a yellow water lily first discovered here. Its red stigma stands out at the flower’s center; beyond Oze, it grows only in parts of Hokkaido and on Yamagata’s Mt. Gassan.
Ozegahara’s deer are seasonal commuters: deep snow keeps them from wintering here, so they move from the Nikkō area in spring and return there for winter. Their browsing now threatens marsh vegetation.
At the Yoppi–Numajiri confluence, Fukushima, Gunma and Niigata meet. Boardwalk planks even bear their maintainer’s brand marks, revealing which prefecture you’re walking through.
In 1948, a plan proposed damming Ozegahara into a reservoir about 8 times the size of nearby Ozenuma. The campaign to save the marsh helped launch Japan’s Nature Conservation Society.
Oze’s boardwalks began as a simple convenience: hikers laid cut logs across the bog because it was so hard to walk. Later, the walkways became essential for keeping footsteps off the fragile peat.
Oze began a national-park “carry your trash out” campaign in 1972. The following year, more than 1,400 rubbish bins were removed, and the idea spread to other places across Japan.
