Onuma Pond, Hachimantai was added to Your Favorites!
Towada-Hachimantai NP, Akita
Claim this place to tell your story your way.
Across from Onuma, the nearby Onuma Mud Volcano still steams in winter; a park ranger reported mud near 95°C in summer. Rising gas piles mud into little volcano-shaped cones—without any lava.
A giant kitagoyō pine in the Onuma woods is described by Akita Prefecture as Japan’s second-thickest. Deep snow buries brush that blocks the approach after thaw, making a close visit a winter or early-spring discovery.
Tiny red sundews fringe Onuma’s southern marsh pools. Their sparkling droplets are sticky traps, not just dew: leaf hairs snare small insects, giving this little wetland plant a carnivorous twist.
In 1953, when winter left Onuma without electricity or telephone, Hatakeyama Kenjiro opened a small inn by the pond. He later campaigned for Hachimantai’s national-park designation and helped build trails and the visitor center.
Old photos from around 1956 show boats on Onuma; local childhood memories add that floating islands once drifted there, and children climbed onto them to play. Today’s viewing deck stands where boat-landing equipment once was.
Hatakeyama Kenjiro, the longtime lakeside innkeeper, recalled a bear that came from the Sumikawa area each year and stood facing his inn. When it stopped appearing, he wondered if it had been shot.
Nearly circular Onuma sits at 944 meters and is about 200 meters across, but its origin is unsettled: some explanations point to volcanic activity; others to water filling a depression beside the Hanawa Fault.
Onuma is gradually shrinking as aquatic plants die, collect on the bottom, and become peat. Over time, that buildup turns open water into wetland—so the pond’s surrounding marsh is part of its ongoing transformation.
