The stone split naturally due to weathering, freezing, and moisture accumulation in existing cracks, rather than human interference.
The high concentration of sulfur dioxide and hydrogen sulfide in the area is a byproduct of the nearby active Mount Nasu volcanic complex.
Historically, the area was known as a 'death zone' where birds and mammals would perish after inhaling concentrated volcanic gases in low-lying pockets.
The legend claims the stone contains the malevolent spirit of a nine-tailed fox who attempted to usurp the Japanese throne during the Heian period.
Before the 2022 split, the stone was officially designated as a National Place of Scenic Beauty by the Japanese government.
The site features a small shrine dedicated to the spirit of the fox, which is regularly maintained by locals.
The Sessho-seki, or Killing Stone, is a volcanic rock formation in Nasu, Tochigi, traditionally associated with the legend of the Tamamo-no-Mae fox spirit. The stone is situated within a high-sulfur zone where volcanic gases, including hydrogen sulfide, naturally emit from the ground. In March 2022, the primary boulder split into two major pieces, an event that drew international attention. The site remains a geological curiosity as the gases historically proved lethal to small insects and animals passing through the area. It is located near the Nasu Onsen hot spring district. A wooden walkway provides visitors safe access to observe the stone and the surrounding barren volcanic landscape. The site is maintained by the Nasu Town local government as part of the Yumoto area's historical heritage. Protective shrines and smaller stone statues, or Jizo, are clustered around the vicinity to appease the spirits associated with the legends.
The viewing platform at the end of the boardwalk, providing a direct view of the split stone against the volcanic slope.
Visit during a breezy day; wind helps dissipate the sulfurous fumes, making the air more comfortable.
Do not wander off the marked wooden paths, as the volcanic soil and gas emissions can be hazardous.
Bring a handkerchief or mask if you are sensitive to strong sulfur smells.
Do not attempt to hike into the surrounding forest off-path, as the ground stability is poor and gas levels are unmonitored.
Stay strictly on designated boardwalks and paths; do not touch or attempt to collect pieces of the volcanic rock.
