Yakehashiri Lava Flow of Hachimantai: A well-preserved monument rife with nature

By Nick Carmon / CIR for Hachimantai, Iwate Pref.

I think most that have been here will tell you that Japan is a place rich with nature.  Not only in terms of quantity of nature but variety. Being a longitudinally “long” country, Japan spans multiple climates, from harsh and snowy Hokkaido to hot and humid Kyushu, with a full range in-between. 

Even within such a green-rich country, I think few regions are as replete with nature as Tohoku, which is rife with a huge variety of hot springs, waterfalls and forests. In Iwate Prefecture’s Hachimantai city, there’s a natural region known as the Hirakasa Uwabo Forest Reserve. Within this reserve is a stretch of land blanketed in black lava chunks, spewed from the nearby Mt. Iwate long ago. This is the Yakehashiri Lava Flow, a wide area covering nearly 150 hectares, and spanning a length and width of approximately 2.8 kilometers and 1 kilometer, respectively. Nationally designated a natural monument in 1952, it also became part of the Towada-Hachimantai National Park when the park was established 4 years later in 1956.

The term yakehashiri in Japanese combines the words yake, for grilling or cooking, and hashiru, for running. No doubt when people at the time saw the red-hot magma racing down the slopes of Mt. Iwate, they felt the name was appropriate!  Fortunately for us today, Mt. Iwate is no longer volcanically active; it is currently thought to have gone dormant in the early 18th century, although what year precisely is still being researched today.

The lava covering the Yakehashiri Lava Flow is jet-black and highly porous, with smaller chunks being the size of an adult fist and larger ones reaching 1 meter in diameter.  The various lava chunks have settled unevenly over the region, resulting in large ripples, creating dips and banks along the ground not unlike deep ocean waves. During the early snowfall season and when the snow begins to melt, this pattern results in the land adopting “stripes” of black and white as the snow fills in the dips, evoking the image of a white tiger.

The truth is that, with Japan being a mountainous country with many volcanoes, leftover lava flows are not actually very strange or unusual, in and of themselves.  However, what makes the Yakehashiri Lava Flow here in Iwate special is how extremely well-preserved it is. Despite research showing that it has existed for over 260 years, the scene remains largely unchanged from when Mt. Iwate originally erupted; neither trees and shrubbery nor natural erosion have significantly altered the landscape, even over more than two centuries.

That doesn’t, however, mean that the area is devoid of flora.  As you walk around, you can see moss and other vegetation growing on the lava rocks, particularly around the edges of the area. And as you look out across the terrain, you’ll see small islands of pine, birch, willow and even cherry trees sprouting here and there, from under the lava. These are spots where the soil has remained rich and fertile even after these years.

The natural area around the lava flow has also attracted other landmarks and facilities. Just across and down the road is an expansive campground area, and nearby that is a telescope observatory, well-placed because of the vast open space around the lava flow. There’s also a natural hot spring, or onsen, nearby.  Appropriately named the Yakehashiri-no-Yu, or Yakehashiri Springs, it’s served by completely natural hot spring water.  They also have a small restaurant using local produce and meat.

I come from Alaska, which is a mountainous place in its own right, with numerous volcanoes among its peaks and valleys.  But while there are leftover lava fields there as well, the Yakehashiri Lava Flow in Iwate was my first time seeing one in person, and I think is unique even among other remnants of its kind.

(Photos courtesy of Nick Carmon)

(Cooperation: Council of Local Authorities for International Relations)

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Nick Carmon

Nick is a second-year Coordinator for International Relations (CIR) living in Iwate Prefecture’s Hachimantai city, in northern Tohoku. His work at the city hall is to help promote tourism by visiting the various shops, landmarks and events to in turn cover and report on them for visitors from abroad.