Naruko is a hot spring town located in northern Miyagi Prefecture. Besides hot springs, the area is also considered the birthplace of traditional kokeshi dolls, and it features several attractive nature spots. One such scenic attaction is Katanuma Lake.
Geological forces over 70,000 years ago created Naruko (sometimes read 'Narugo') Volcano. The oldest written historical records tell of an eruption in 837 that gushed out hot water like a river through the rural countryside hamlet. The event created the lake and lead to the discovery that the hot underground water could be rejuvenating for the body. It was soon after that the townspeople built a shrine to honor the newfound "hot spring god" and began constructing hot springs to enjoy themselves. A visit to the lake is a 15 minute taxi ride or about an hour walk into the mountains (using a paved road) from Naruko-Onsen Station.
A visit to the lake allows you to soak up historical origins and lush nature. You could also rent a paddle boat from the onsite restaurant/resthouse. Enjoy great views of the lake over coffee made with hot spring water or the special: grilled lamb. Taking an easy stroll along the 1.3 km loop hiking trail around the lake is a must. When walking the wide, clear, and flat path, visitors will be hugged by the blue of the lake and the green of the mountain forest. The colors of autumn bring the whole area to life infiery reds and oranges. A few small steam vents are located steps away from the parking lot on the trail. The incredibly clear lake is 16.2 meters at its deepest point, but you won't find any fish here. The volcanic activity makes this one of the most naturally acidic lakes in the world. As such, the lake never completely freezes over in winter.
As a word of warning, do keep in mind that you will be sharing the trail with the resident miniature swarms of black flying insects. They will not sting, bite, or follow you. Just mind where you are walking and try to avoid them if you don't want them on your clothes. These are only at the lake area and not around other parts of Naruko.
Katanuma Lake has another name: the "Lake of the Dragon God". This lake, similar to several others in Japan, is said to be home to a dragon. This dragon is female. It is said she can be heard weaving from the bottom of the lake every year during the Doll Festival (March 3).