Exploring Mount Nasu’s Sesshō-seki: Legend, Geology, and History

Nine-tailed fox Tamamo-no-Mae in Nasu's autumn landscape.

In Nasu, Tochigi Prefecture, lies a stone steeped in mystery and legend: the Sesshō-seki, or “Killing Stone.” This enigmatic boulder is said to be the transformed remains of a malevolent nine-tailed fox, Tamamo-no-Mae, whose spirit lingers in the area. The stone’s location on the slopes of Mount Nasu, near Nasu Yumoto Onsen, adds to its allure, drawing visitors eager to explore its mythical and geological significance.

Sessho-seki(殺生石 せっしょうせき) in Nasu Town, Tochigi Pref., Japan
“Sessho-seki, Tochigi 01” by Σ64, CC BY 3.0, via Wikimedia Commons

What is the Sesshō-seki (Killing Stone)?

FACT: The geological reality

The Sesshō-seki is a volcanic rock located beside one of Mount Chausu’s vents, which emit toxic gases such as hydrogen sulfide and sulfur dioxide. These emissions have historically been lethal to small animals, a fact noted by the famous haiku poet Matsuo Bashō during his visit in 1689. He observed that bees and butterflies lay dead so thickly around the stone that the sand beneath was obscured. This natural phenomenon adds a layer of eerie reality to the legend, as the stone’s lethal aura is not entirely mythical.

Visitors today can witness the same natural conditions that have inspired legends for centuries. The volcanic activity in the area, characterized by the emission of these noxious gases, creates a unique environment where the boundary between myth and reality blurs. The stone itself, with its mysterious aura, stands as a testament to the power of nature and the stories it inspires.

Nine-tailed fox Tamamo-no-Mae in Nasu's autumn landscape.
AI生成イメージ / AI-generated illustration (not a photograph of the actual place)

The Legend of Tamamo-no-Mae and the Nine-Tailed Fox

LEGEND: The story of Tamamo-no-Mae

According to local legend, Tamamo-no-Mae was a beautiful woman who served the emperor but was later revealed to be a wicked nine-tailed fox in disguise. After her true identity was discovered, she fled to Nasu, where she was eventually killed by the emperor’s troops. Her body is said to have transformed into the Sesshō-seki, a stone that continued to exude a malevolent aura and noxious gases, embodying her lingering spirit. This tale of transformation and lingering malevolence is central to the stone’s legendary status.

The story of Tamamo-no-Mae is not just a tale of deceit and transformation but also one of enduring cultural significance. The legend has been passed down through generations, becoming a part of the local folklore that shapes the identity of Nasu. The stone, as a physical reminder of this tale, continues to captivate visitors who are drawn to its mysterious past and the supernatural elements that surround it.

LEGEND: The monk Gennō’s intervention

Centuries after the fox’s demise, a Buddhist monk named Gennō is said to have visited Nasu during the Muromachi period. According to legend, he shattered the Sesshō-seki with his ritual power, breaking it into three pieces. These fragments were scattered across Japan, with one landing in Fukushima and another in Hiroshima. This tale is dramatized in the Noh play “Sesshōseki,” highlighting its cultural significance. The story of Gennō’s intervention adds a layer of spiritual redemption to the narrative, suggesting that even a cursed object can be subdued by righteous power.

The legend of Gennō’s intervention is celebrated in various cultural expressions, including traditional Noh theater, which brings the story to life through performance. This dramatization not only preserves the tale but also allows audiences to engage with the themes of redemption and the triumph of good over evil. The enduring popularity of such performances underscores the deep cultural roots of the Sesshō-seki legend in Japanese society.

20090321那須岳Tagged - Mount Nasu
“20090321那須岳Tagged” (Mount Nasu) by BehBeh, CC BY-SA 3.0, source, via Wikimedia Commons

Volcanic Geology and Toxic Vents at Mount Nasu

FACT: The natural environment

Mount Nasu is an active volcanic range, and the Sesshō-seki is situated near its vents. The sulfurous gases emitted from these vents contribute to the area’s eerie atmosphere and have been a part of the local folklore for centuries. The combination of natural phenomena and myth makes the site a fascinating destination for both geologists and those interested in Japanese legends. Visitors to the area can witness the interplay between natural forces and cultural narratives, as the landscape itself seems to breathe life into the legend.

The geological features of Mount Nasu provide a compelling backdrop to the legend of the Sesshō-seki. The active volcanic vents, with their continuous emission of gases, create a dynamic environment that has long captured the imagination of locals and visitors alike. This natural setting enhances the mystical aura of the site, making it a unique place where the lines between science and legend converge.

Matsuo Basho and Historical Literary Ties

FACT: Basho’s observations

Matsuo Bashō, one of Japan’s most revered poets, visited the Sesshō-seki during his travels. His observations of the dead insects around the stone are recorded in his writings, providing a historical account that ties the legend to real-world phenomena. Bashō’s notes add a layer of literary depth to the site’s history, bridging the gap between myth and reality. His writings serve as a testament to the enduring power of the Sesshō-seki’s legend, capturing the imagination of artists and thinkers across generations.

Bashō’s reflections on the Sesshō-seki highlight the stone’s impact on cultural and literary traditions. His poetic insights offer a unique perspective on the legend, illustrating how the natural and supernatural elements of the site have inspired artistic expression. Bashō’s work continues to resonate with those who visit the site, offering a poetic lens through which to view the mysterious landscape.

20090418那須岳 - Mount Nasu
“20090418那須岳” (Mount Nasu) by BehBeh, CC BY-SA 3.0, source, via Wikimedia Commons

The Annual Gojinkasai Festival

FACT: Rituals and traditions

Each year, the Gojinkasai festival is held on the last Sunday of May to appease the spirit of Tamamo-no-Mae. Participants carry torches from Nasu Onsen Shrine to the Sesshō-seki, accompanied by the rhythmic sound of drumming. This ritual underscores the enduring cultural impact of the legend and its integration into local traditions. The festival is not only a spiritual event but also a vibrant cultural celebration, drawing both locals and tourists who wish to experience the living traditions of Nasu.

The Gojinkasai festival is a vivid expression of the community’s connection to the Sesshō-seki legend. The torch-lit procession and drumming create a dramatic and immersive experience, allowing participants to engage with the story in a tangible way. This annual event serves as a reminder of the legend’s lasting influence and its role in shaping the cultural landscape of Nasu.

Tips for Visiting Nasu Yumoto Onsen and Sesshō-seki Safely

FACT: Current conditions and events

In March 2022, the Sesshō-seki was found split in two, prompting the town to hold a memorial prayer ceremony. Visitors to the site should be aware of the potential hazards posed by the volcanic gases and are advised to check the official website for current hours, fees, and access information to ensure a safe visit. The splitting of the stone has added a new chapter to its legend, sparking interest and speculation about its significance and future.

The recent splitting of the Sesshō-seki has reignited interest in the stone’s legend, with many speculating about its implications. This event has added a contemporary layer to the narrative, inviting both locals and tourists to reflect on the stone’s historical and cultural significance. As the site continues to evolve, it remains a focal point for those interested in the intersection of legend, history, and natural phenomena.

Nearby Guide

Access

  • Nasu Yumoto Onsen Bus Stop (Nasu-machi) — From JR Kuroiso Station, take the Kanto Bus bound for “Nasu Yumoto Onsen” (about 50 minutes), then walk about 10 minutes from the “Nasu Yumoto Onsen” bus stop. details

Nearby sights

  • Mount Chausu and Ropeway (Nasu-machi) — An active volcano offering a ropeway ride with panoramic views. The gondola climbs from 1,390 to 1,684 meters in about four minutes. In late September and early October, the slopes below turn vivid red. Bus from Nasushiobara or Kuroiso station in season. official site
  • Shika-no-yu (Nasu-machi) — Nasu’s original bathhouse, named for a wounded deer said to have led a hunter to the spring. Inside the dark wooden hall are small pools graded from about 41°C to 48°C. No soap or shampoo; bring a towel. Strongly acidic sulphur water — remove silver jewellery. official site

Where to stay

  • Hotel Sun Valley Nasu (Nasu-machi) — A forest resort spread across a vast estate, offering diverse accommodations, hot spring facilities, and restaurants. details

Where to eat

  • La Vita e Bella Nasu Kogen (Nasu-machi) — A resort-style Italian restaurant where guests can enjoy seasonal ingredients and locally grown vegetables. details
Locator map of Japan: Nasu, Tochigi
Legend site: Nasu, Tochigi — Source: Map of Japan with highlight on 09 Tochigi prefecture.svg; Map: Lincun, CC BY-SA 3.0, via Wikimedia Commons

Sources

About the author

JAPAN ESSENCE Editorial Team
Our mission is to bring you Japan’s legends, myths, festivals and living traditions, through both historical fact and the stories passed down over generations.

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