Set Off on a Sensory Journey That Rewinds Time by 350 Million Years
24/5/10
“I’ve always been a restless soul. I’m not good at doing the same thing over and over—I’m always seeking change and something new.”
With a bright, open smile, Manami Sadano shares this about herself. She serves as a member of “Mine Charm Discovery” (a Local Revitalization Specialist) in Mine City, Yamaguchi, where she works as a caving guide.
The “Mine Akiyoshidai Geopark” is celebrating its 70th anniversary as a Quasi-National Park in 2025 and is currently aiming for UNESCO Global Geopark certification. Sadano enters Akiyoshido—one of Japan’s largest limestone caves—three to four times a week to share its profound allure with visitors.
While one might expect the cave to become “monotonous” after so many visits, she shakes her head with sparkling eyes: “No matter how many times I enter, Akiyoshido never loses its sense of scale. There is always something new waiting inside.”
Today, Sadano lives a life intertwined with caves, yet she says she grew up as an indoor child, far removed from nature. What was the turning point that shifted her values by 180 degrees? How did she arrive at her calling as a caving guide? We traced the trajectory of her journey.
Opening the Door to Exploration: A “Messy Lunch Box” in the Rain
Growing up in Kitakyushu City, Sadano recalls, “Nature was nearby, but my whole family was the indoor type. I have no memory of going mountain climbing or swimming in the sea.” The experience that would shake her values came when she was in the fifth grade.
Participating in a five-day event called “Challenge 100km” organized by a local youth nature center, she encountered heavy rain while trekking along a mountain path.
“I ate my lunch box, which had become a soggy, messy mix in the rain. Yet, it tasted unbelievably delicious—as if it were soaking into my exhausted body. It was a sensation I had never experienced before. The view from the summit was truly beautiful, and from that moment on, I began to see nature in a deeply positive light.”
This powerful experience sprouted the seeds of an adventurous spirit that had been dormant within her.
That adventurous spirit fully blossomed during her time with the Ritsumeikan University Exploration Club. On a welcome trip for new students to a cave in Okayama, she felt her heart leap during the extraordinary experience of splashing through water.
She was instantly captivated by the allure of caving, particularly immersing herself in “vertical shaft exploration”, where explorers descend using ropes.
Starting with basic climbing drills using trees, she steadily acquired advanced techniques for navigating complex terrain and rescue training to support her teammates.
Then, an event occurred that further fueled Sadano’s sense of adventure. While looking for new cave exploration sites abroad, she received word through a mutual acquaintance: “There is only one caver on Sumba Island. It seems he’s in trouble because he doesn’t have enough people to progress with the survey.”
She immediately contacted him and received a reply: “There are over 100 unexplored caves on the island. Please come and help me survey them.”
Today, Sadano lives a life intertwined with caves, yet she says she grew up as an indoor child, far removed from nature. What was the turning point that shifted her values by 180 degrees? How did she arrive at her calling as a caving guide? We traced the trajectory of her journey.
Opening the Door to Exploration: A “Messy Lunch Box” in the Rain
Growing up in Kitakyushu City, Sadano recalls, “Nature was nearby, but my whole family was the indoor type. I have no memory of going mountain climbing or swimming in the sea.” The experience that would shake her values came when she was in the fifth grade.
A Message Received in Spain
Following these great adventures, Sadano worked as a cram school teacher after completing graduate school, but her quest for the unknown never faded. Her longing for the unexplored only grew, leading her to leave Japan for a time. A year spent in Spain on a working holiday further enriched her outlook on life.
“People in Spain put all their energy into enjoying life. They work moderately and plan their leisure meticulously. Being immersed in a culture where people don't worry about others' opinions and instead value what they truly love was liberating. I simply realized, ‘I want to do what I love,’ and I found myself becoming more accepting of all kinds of people—my capacity for tolerance expanded.”
As her time in Spain was nearing its end, she received a message. It was from Takashi Murakami (former Vice President of the Speleological Society of Japan), a Mine City official who had supported her during her university visits to Akiyoshido and served as her mentor in caving. He asked, “We are looking for a cave guide in Mine City. Would you be interested?”
“Even though I had spent so much time in caves during university, the idea of making it a profession had never crossed my mind. But when the thought hit me—‘I might be able to work with the caves I love’—I was overcome with excitement. I accepted immediately.”
Experience the Infinite Scale of Time and Depth
Returning to Japan, she applied to Mine City and was appointed as a “Mine Charm Discovery” Member in October 2024. Her days as a guide, leading general tourists, began.
“Every visitor is unique in their physical strength, interests, and reactions. Even with the same explanation, just by tweaking the delivery or the sequence of information, the level of surprise and understanding changes significantly. That is truly fascinating.”
Currently, in addition to the safety management knowledge she cultivated in the exploration club, she is intensely studying speleology. She continues to polish her skills daily to deeply convey everything from the formation of caves to the hidden stories within. However, what Sadano wants to convey is more than just mere facts.
Stepping beyond the railings of the general tourist area, descending steep slopes by relying on wedges, and reaching the banks of a river deep underground—when headlamps are extinguished, total darkness and the sound of the babbling river envelop the participants. When the lights are flicked back on, white stalactites, formed over an eternity, reveal their majestic forms.
“I want people to feel the unimaginable scale of hundreds of millions of years and this profound depth with their own skin. Stalactites that take over 100 years to grow just 1cm are hanging here in such abundance. By experiencing that reality up close, I hope it inspires a desire to preserve this nature.”
Sharing the Allure of Akiyoshidai—Wider and Deeper
For Sadano, there is a decisive difference between Akiyoshido and other caves. “In most Japanese caves, they start to feel smaller every time you enter. Your path becomes optimized, and the ‘distance’ between you and the cave shrinks. But Akiyoshido stays vast no matter how many times I go in. The space is so immense that it allows me the room to truly look around, and every visit yields new discoveries—like, ‘Oh, there was a living creature in a place like this,’ or ‘This crevice looks different than before.’ Even for someone as restless as me, I never grow tired of this place.”
The term for her current position is limited to three years. When asked about her vision beyond that, she says, “I don’t know yet, but I love Yamaguchi Prefecture, so I want to continue my work here.
Right now, caves are the primary focus, but walking the karst plateau of Akiyoshidai also feels incredible. I can envision various projects, such as combining E-bikes with caving so visitors can immerse themselves in nature all day long.”
She feels that her personality—always preferring the new and seeking constant change—is “perfectly suited” for this role of exploring new forms of tourism.
An indoor girl who opened the door to nature through a messy lunch box in the rain, traveled the world, and returned to this land—Sadano’s adventure has only just begun. The story of Akiyoshido, told through her eyes, will continue to illuminate the hearts of many.
Manami Sadano
Caving Guide / “Mine Charm Discovery” Member
Born in Kitakyushu City, Fukuoka Prefecture, she discovered her passion for caving through the Ritsumeikan University Exploration Club. Since her university years, she has gained extensive experience as an explorer both in Japan and abroad, including participating in cave surveys on Sumba Island, Indonesia.
After completing graduate school, working as a cram school teacher, and spending a year on a working holiday in Spain, she assumed her current position in October 2024. Guided by her passion for “landscapes no one has ever seen” and a profound reverence for the Earth, she conducts specialized caving tours in the non-public areas of Akiyoshido Cave. Her activities serve as a vital force in sharing the charms of the Mine Akiyoshidai Geopark both domestically and internationally.