Cave Explorer Katsuji Yoshida on the Skills for "Coming Back" from the Dark and the Danger of Panic

What Yoshida does to avoid getting lost is memorize the view when looking back. In an unfamiliar cave, you tend to move forward while looking all around, curious about what lies ahead. If you do that, the first time you actually see the way back is when you turn around to leave, and it becomes "scenery you've never seen." So Yoshida made a habit of repeating a routine: after moving about 5 m forward, turn around, observe the view of the way back, commit it to memory, and then continue. Since starting this, Yoshida has hardly ever gotten lost.

Before that, there were some dangerous moments. Early on, Yoshida used to go into caves completely alone. Once, unable to find the way back, Yoshida kept circling the same spot for about two hours, only realizing it was the same place on the second or third lap. But why the loop was happening, or where to break out of it, remained a mystery. Going the other way, backtracking, going around 10 times, 20 times, Yoshida's stamina drained away, and their mental state was worn down too: "I'm never getting out of here." Giving up easily would have simply meant dying, so Yoshida retraced every movement from memory, and was able to get back only because they managed to recall it all. Looking back, Yoshida says it was "just luck."

As the reason for thinking this way, Yoshida points to having come across a number of people who died inside caves. Yoshida hasn't looked into how old the remains were, but has encountered quite a few people who never made it out of caves, from someone who died a year earlier to people from 100 or even 1,000 years ago. That's why Yoshida's conclusion is that "you absolutely should not go in alone."

Yoshida first entered a natural cave at age 28. Already interested in the unknown, Yoshida spotted a notice for a caving club in an outdoor magazine and called the number listed. That was the beginning. Later, when Yoshida asked the club's president, "You must have gotten a lot of calls," the answer was that Yoshida had been the only one. That's when Yoshida understood just how niche the world of caving was.

The expeditions that senior members took Yoshida on were so much fun that Yoshida wanted to do them even at the expense of work. Around then, a senior member said, "Caving is fun, but once you explore a cave you found yourself, you'll never be able to quit." If just being taken along was this enjoyable, what would a self-discovered cave be like? From that day on, Yoshida began roaming the mountains in search of caves, at first working alone.

For Yoshida, the most moving moment in exploration is finding an untouched world. Coming upon a huge space at the bottom of a vertical shaft brings an intense thrill — the thrill that no one has ever been there, and that you are witnessing it as the very first person. "That's why I can't quit," Yoshida says.

Occasionally, too, there are spectacular sights that come as "a kind of reward." A tremendously large space where the floor is almost flat and the walls sparkle with crystals. Terraced pools stepped like rice paddies, filled with highly transparent water and crystals — the kind of place you light up and photograph. Beautiful groundwater pooled deep underground, underground rivers, waterfalls. But such places aren't all that common, so when Yoshida finds one, the reaction is "Yes!"

On the other hand, Yoshida admits that when watching footage of themself on camera, the moment they're smiling most and happiest is — though it may defeat the purpose — the moment of exiting the cave. Yoshida keeps taking on the unknown and being moved by it, but somewhere inside there's always a desire to go home. Yoshida also says that when you dig deeper into cave stories, they gradually turn into stories about death.

There have been many moments when Yoshida went pale. When you squeeze through a narrow space twisting your body, you can touch a brittle ceiling and bring it down. Once, a collapse completely buried Yoshida from the waist down. By chance, a companion was right behind and removed the buried rocks one by one from behind, which is how Yoshida made it back. Had Yoshida been alone, "I wouldn't be here now." If the rocks had piled up a bit higher than the waist, breathing would have become impossible, so that too was luck. Since then, Yoshida has made a rule never to touch brittle rocks overhead in tight spaces.

Another incident happened early in Yoshida's caving career. Lacking experience, Yoshida went headfirst down a narrow, mud-covered slope of about 45 degrees. Having gone in headfirst, there was no way to push off the ground with the feet to get back. On top of that, the hole narrowed the further it went, leaving no room to twist or move the hands. Before Yoshida knew it, they were stuck upside down, unable to move. That time, Yoshida was alone.

No amount of twisting brought any progress upward, and only the fingers could still move. Yoshida pushed against the wall with their fingers, raising their body ever so slightly, but relaxing for even a moment meant sliding all the way back down because of the mud. Repeating this over and over, Yoshida managed to escape after one to two hours. If Yoshida hadn't come up with that technique, they might still be bones in that narrow crevice today — and in fact Yoshida has come across people inside caves who died exactly that way.

Some accidents can't be avoided by your own judgment alone. While exploring an unexplored vertical shaft in China, Yoshida's team descended on ropes to a depth of about 300 m — roughly the height of Tokyo Tower. With the exploration done and the team pulling out, companions began climbing the wall first. Then a companion about 100 m above accidentally kicked loose a rock underfoot.

Hearing the rock hit the wall — "clang, clang" — Yoshida pressed against the wall to reduce the chance of being hit. About three seconds after hearing the second clang, the rock came down, struck the left edge of Yoshida's helmet, deflected, and slammed directly into the shoulder. The speed and weight of the rock sent Yoshida flying, and in that instant Yoshida thought, "I'm dead." The left side of the body went completely numb, unable to grip anything.

At first Yoshida lay there, but realizing that a second rock hitting them would mean certainly not getting out alive, Yoshida hurriedly stood up and began climbing one-handed. A shaft that would take about 12 hours to climb with both hands took about 30 hours that time.

After reaching the top and explaining, "It hit me, it's probably broken," nobody believed it, because Yoshida seemed so lively. Only after stopping in a large Chinese town and getting an X-ray at a hospital, and showing the image, did people say, "Yep, it's broken." The person who had dropped the rock said, "Good thing it was you, Yoshida." What they meant was that anyone else would have died, and that with that many fractures you'd normally need a rescue — it's rare for someone to make it up on their own.

Yoshida's own view is that as long as you're alive, everything is OK. You can keep exploring, and you can return to the world you were born and raised in. Injuries come with the territory when you explore. And since Yoshida only goes caving with companions they could forgive even for dropping a rock and injuring them, there was no anger, as it wasn't intentional; it ended with everyone laughing together, "Glad it turned out OK."

Yoshida says they've broken nearly every part of the body from the neck down. Not the spine, cervical vertebrae or skull, but fingers, ribs, shoulders and so on — pretty much the whole set. Even so, Yoshida doesn't count fractures as real injuries. You can break any number of bones and not die.

What's frightening, Yoshida explains, are open wounds. If you cut a major blood vessel, stopping the bleeding is hard, and in caves where you have to dive back through muddy passages, infection becomes a concern. A fracture won't kill you right away, nor does it carry the risk of infection; you just endure the pain and focus on getting out of the cave. So when Yoshida hears a companion has broken a bone, Yoshida ends up beaming with delight: "Minor injury — lucky!"

Yoshida is grateful to their parents for such a sturdy body. Yoshida brings fresh food into caves and doesn't throw away meat or vegetables even when they spoil, eating them anyway, but has no memory of ever getting an upset stomach. Yoshida will also drink water with mosquito larvae in it. Yoshida sometimes goes caving before a fracture has healed, and has even gone on an expedition wearing a cast. When the attending doctor saw the cast covered in mud and scratches and asked why, Yoshida answered, "I fall down a lot," and the doctor, clearly knowing it was a lie, said, "Well, fine."

What Yoshida describes as "genuinely almost dying within the past two months" happened while exploring a cave whose existence Yoshida had known about for some time. A few dozen meters in from the entrance, it was flooded; at the time it couldn't be dived and had remained unexplored. Yoshida went there with Takashi Takeuchi, known as "Kō-chan," who is both Yoshida's apprentice and partner.

The underwater passage was very narrow, so from the start they removed their tanks and held the two in front of them, putting their faces between the tanks as they advanced. In cross-section, the passage dropped at an angle of about 30 degrees and then turned sharply upward in a V shape. Yoshida felt fear, but the urge to go was too strong; pushing the tanks ahead, they broke through and came out into the next air-filled space. Beyond that, the passage grew even narrower, but they dove and dug through sediment as they advanced. Around midnight, with their stamina nearing its limit, they decided to head back for the time being.

But the muddy water stirred up by their digging had flowed downstream, and the entire narrow waterway they had come through had turned to mud. They had to return without being able to see anything at all. At the V-shaped section, pushing the tank didn't make it rotate to fit the shape of the passage, and no matter how hard Yoshida pushed in the blindness, there was nowhere to go. Overwhelmed by fear, Yoshida began to think the passage they'd come through might have been buried by a landslide, and to reset, backed out in reverse to the air-filled space further in.

There, the two confirmed that the guideline marking the way back had ended up in a hard-to-follow position, and adjusted it by loosening the parts that had been pulled too taut. But Yoshida says the second attempt is mentally harder. When you go back to a place you couldn't get through once, your confidence that you can break through shrinks dramatically. "It's just too scary," and your mind can't hold up. So Yoshida tried to think of nothing but breaking through the narrow section.

Going forward again, the tank still wouldn't pass. Remembering that the passage rose in a V, Yoshida reached in and felt the cave seemed to continue upward, so inserted the tank and pushed it up hard — and it popped through into the space beyond. But next, just as Yoshida's face fit between the tank and the ceiling, a rubber piece attached to the regulator snagged and simply wouldn't come free. Unable to move, the fear kept growing. Yoshida estimated that the air in the tank would probably last only about 20 to 30 minutes.

Since panicking only makes things scarier, Yoshida focused solely on freeing the snagged rubber. If it hadn't come free within another five minutes, Yoshida would probably have cut it with the knife in their gear. In the end, the rubber came loose. Yoshida says that when a person who's been cornered manages to do one thing they couldn't do before, they feel a little more at ease. From there, still unable to see, Yoshida reasoned that whatever direction the tank could be pushed was the way back, kept pushing, got through the final narrow section, and made it out alive. Once outside, the two said to each other, "That was scary," "That was close," and Yoshida told Kō-chan that there hadn't even been room to give advice along the way — "I just had to trust you." In the video, Yoshida says this expedition ranked among the three most nerve-wracking in ten years.

In expeditions where death is always close by, the one thing Yoshida can call enjoyable is eating. Meals are for nutrition, but equally important, they serve as a "mental reset." Even when you're mentally cornered or worn out, your mood softens as you eat.

On expeditions where food can be carried in, they often make hot pot. Yoshida frequently makes a red-miso-based hot pot, bringing in napa cabbage, green onions, pork, burdock root and so on. Coolers can't be brought into caves, so ingredients carried at room temperature start to spoil within a few days. So they add things to the pot in the order they start to go bad. On expeditions where food can't be brought in, they pack nuts, dried fruit, gummies, seeds and the like into waterproof cases and eat a little at every break. No fire or water is needed, and you can eat even while hanging from a rope.

At the end of a day's activity, eating instant ramen after changing into dry clothes and before getting into the sleeping bag is, for Yoshida's team, a "cave feast." Sometimes they even catch shrimp in the cave and grill them. When grilled, they turn red just like store-bought shrimp, and peeled and dipped in soy sauce, they're delicious. Yoshida has also caught and grilled eels, but doesn't do that often.

Bodily waste is carried out of the cave. Urinating directly would make the cave smell and damage the environment, so urine is collected in plastic bottles and disposed of outside. Since everyone prefers to use their own bottle, the number of bottles keeps growing, but it's easier to carry if it's consolidated into a large container. So whoever loses at rock-paper-scissors has to transfer everyone's urine into the big container. Because this is the most hated job, everyone plays rock-paper-scissors in deadly earnest. It might be the loudest, liveliest moment inside the cave, Yoshida says with a laugh.

Feces go into zip-top bags, with the air squeezed out, and are carried out in multiple layers of bags so they don't leak or burst. At base camp they can be stored in a hard case, but while on the move there's no container to put them in. So a common method is to put the bagged feces in the empty space inside the helmet and wear it. That's the most readily available hard case. They started doing this because a bag once stored in a chest pocket burst in a tight squeeze. For Yoshida it's like an "explosive," and though it's truly unpleasant, Yoshida puts it in the helmet and wears it.

As the reason waste must not be left behind, the narration points out that a cave is a closed environment, and once it's contaminated, the effects linger for a long time. And caves are home to creatures with their own unique ecology.

According to Yoshida, there are various lineages of cave ecosystems, but a representative one starts with bats. Bats eat insects outside, then perch on the ceiling and drop guano. The guano piles up, mold grows on it, tiny insects eat the mold, and carnivorous insects eat those tiny insects. They're at most about 1–2 cm in size, and since caves contain almost no organic matter, the ecosystem barely holds together by sharing or fighting over scarce food.

On the other hand, surprisingly large creatures can live in the cave's water systems. Giant mottled eels can grow as long as about 3 m, and they're found in caves as a matter of course. Yoshida explains that underwater cave passages are often connected to rivers on the surface, and food washes in from those rivers, which allows fish, eels, crayfish-like creatures, crabs and others to live there.

Because sunlight doesn't reach them, creatures deep in caves are pure white, and some are so translucent you can see their internal organs. Yoshida roughly divided cave creatures into two groups. Troglophiles are creatures that favor the cave environment but also exist outside caves, and they have eyes. Troglobites are so adapted to caves that they would die if taken outside; in place of eyes, some have antennae about ten times longer, sense their surroundings with various parts of their bodies, or breathe through their entire skin.

Yoshida believes there are still undiscovered species among these creatures. In fact, Yoshida has seen a creature with a crab-sized body and long, spider-like legs clinging to an underwater wall that darted away when approached, but didn't manage to catch it. Yoshida hasn't investigated whether it's a new species, so it's unknown; a specialist scientist would probably ask, "Why didn't you catch it?"

What Yoshida says must be avoided above all in a cave is panic. Yoshida describes the state just before panic as "your soul starting to separate from you." When you're calm, your soul is firmly attached to your body, and you can control both your body and your mind. When you panic, you stop being yourself and go half-mad, unable to control yourself.

As Yoshida explains it, first your pulse speeds up, then your breathing becomes shallow. The rhythm of inhaling and exhaling falls apart, and you may keep inhaling without being able to exhale. When your breathing is disrupted, your body tenses up, you can't take in enough oxygen, all sorts of problems arise, and you become terribly fatigued. Everything turns against you. So when panic starts to set in, you suppress the fear with everything you have. If a companion is on the verge of panic, you calm them down by saying, "It's OK, we're definitely getting out alive, this is a piece of cake." The narration sums up that, according to Yoshida, panicking in a cave leads only to death.

Yoshida says they have spent about ten years analyzing their own behavior when backed into a corner. One idea Yoshida has been talking about in lectures lately is "narrowing your mental field of view." When people are cornered, they think only of bad things. If this happens, I'll die; if that happens, I won't make it back — and as you think this way, your body shrinks back, you can't do what you'd normally be able to do, and you can't come up with what you'd normally think of. So you narrow the scope of your thinking drastically and use your mind only for pinpointing what you need to do right now. You don't think about the worst-case scenario at all. Strangely, that makes the fear much smaller. Yoshida adds that this may only make sense to people who have experienced it.

Another method came from lecturing experience. Yoshida describes themself as someone who gets nervous easily and was bad at speaking in front of people. When first asked to give lectures, nerves would wipe Yoshida's memory, and Yoshida would read the script at breakneck speed and then run out of things to say. So, with the simple idea of buying time, Yoshida tried deliberately speaking slowly. Afterward, Yoshida realized they hadn't been nervous.

Applying this, Yoshida connected moving slowly with not getting nervous. Gear that would normally be snapped off and on is handled one step at a time, slowly — "Removed it," "Attached it" — and the tension during that time diminishes. Even so, the tension doesn't drop to zero. As an even better way to avoid nervousness, Yoshida suggests closing your eyes. Rather than narrowing your field of view, you shut it down entirely and reduce the incoming information. Put into words, it's "escaping reality," but if you carry out actions with your eyes closed, you can get through them without tension.

Yoshida compared mental strength to a mille-feuille. You don't suddenly become strong one day; it builds up little by little through accumulating experiences of running into accidents, somehow getting through them, and coming back alive. That, Yoshida says, is "absolutely" true.

Yoshida believes risk can never be zero, and there's no such thing as an expedition from which you're 100% guaranteed to return alive. That said, there are ways to reduce risk. Preparation is obviously important, but when trouble arises — for example, when you've forgotten a piece of gear — you don't do anything out of the ordinary, like making do with a substitute. If something bothers you even slightly, you reset and start over. If you push too hard and die, you'll never get any further. With not losing your life as the top priority, Yoshida now turns back "without a second thought." "Too bad — let's go eat something good and head home" is the best survival technique, Yoshida says.

This thinking comes from regret. On expeditions done in partnership with TV programs, even when batteries ran out and had to be recharged outside, or someone had to go back for something forgotten, the importance of getting good footage led Yoshida to push a little too hard to produce results. Yoshida says they nearly died three times during joint projects with TV shows, and reflects that it was because of misjudgments. Since then, Yoshida has made their own judgment the top priority and withdraws when needed.

Yoshida also spoke about their view of life and death. From the moment people are born, it's certain they will die, and no one knows when. To those who look at explorers and say, "That person will die young," Yoshida's response is that the same goes for them. If anything, people who explore go to what others might consider excessive lengths to avoid accidents and sudden incidents even in daily life. That's why Yoshida says they're confident they won't die easily.

As one of the experiences that shaped Yoshida's view of life and death, Yoshida described carrying a body out of a cave. About ten years ago, a companion found what looked like a report on a cave Yoshida had previously explored, went to check it out since it seemed interesting, and discovered what appeared to be a body. When the companion called, Yoshida asked, "Did you confirm it?" They hadn't. Since even a photo would allow next steps like reporting to the police, Yoshida decided to go confirm it.

The call came around 6 or 7 p.m. Yoshida gathered whoever could come, climbed the mountain, and reached the cave entrance around midnight or 1 a.m. After setting up ropes and descending, they found the deceased in a narrow spot at the bottom of a roughly 30 m shaft. The photo was taken around 2 a.m., and by the time they had left the cave and reached the police, it was around 5 a.m.

The deceased was a man in his 60s. According to the narration, based on circumstances that came to light later, it's thought he came back as an adult to see a hole in the mountains he'd known as a child, and fell in. It was a shaft over 30 m deep, with no way back to the surface. Yoshida reportedly suspects he lost his strength in the darkness and gradually weakened.

Yoshida says that because they also sleep in caves, they can intuitively understand. When you open your eyes in a cave, you see nothing, and even an explorer is momentarily confused — "Where am I? Oh, a cave?" So Yoshida can imagine that the man repeatedly fell asleep and woke up, not knowing whether he was alive or dead, growing weaker until he passed away as if falling asleep. Yoshida doesn't think he died in agony, and says that makes them feel a little better.

A few days after the report to the police, Yoshida got a call. The police had consulted rescue teams and even the Self-Defense Forces, but because the environment — the bottom of a 30 m shaft — was so unusual, they concluded they had no choice but to leave the recovery to Yoshida's team. The man was believed to have died about a year and a half earlier, yet both flesh and bones remained. According to Yoshida, because caves have few decomposing bacteria, the body was in a state like a "wet mummy," and remaining that way for a year and a half was apparently unprecedented; forensic investigators from all over the country gathered, saying they wanted to examine it.

Yoshida's team proposed to the police that it wouldn't be difficult if they separated the head, arms and torso into individual bags. But for forensic reasons and out of consideration for the family's feelings, the police said they wanted the body brought out as intact as possible, which put the team in a bind. What came to Yoshida's mind then was Egyptian mummies, and the idea of wrapping the body round and round with duct tape. The next day, Yoshida had the police buy about ten rolls of duct tape, and decided to attach handles during the wrapping process. A stretcher has places to hold, but a body simply wrapped in duct tape doesn't. With this, Yoshida felt relieved that it should be possible to carry it through narrow spots.

But a problem arose at the hoisting stage. Neither the body bag nor the duct tape was fully waterproof, and when suspended in midair, bodily fluids pooled at the bottom, leaked under pressure, and rained down on the person guiding it from below. There were screams, but no one was going to die from it and they couldn't stop partway, so Yoshida called down from above, "Bear with it!" and kept hoisting. Then, after raising it to the ceiling, it had to be moved about 30–40 m horizontally over the 30 m-deep hole. To avoid dropping it, people braced themselves against the walls to form a platform and pulled it across on top of them, so everyone serving as the platform ended up covered in bodily fluids too. The recovery took about 20 hours.

Yoshida says that while the death was a sad event, they were able to carry him out using all their skills. The family had spent a year and a half with him missing, not knowing if he was alive or dead. It was an unfortunate outcome, but the man's father was glad, saying, "Now I can hold my son's funeral," and Yoshida recalls being deeply moved. Recently, Yoshida visited that cave for the first time in over ten years and uploaded a video to their YouTube channel.

Even when lives aren't at stake, there are things Yoshida would rather not encounter. Yoshida especially can't stand cockroaches; running into them is "the ultimate" in unpleasantness. In Southeast Asian caves there are holes swarming with cockroaches, making exploration impossible. While the ceiling and walls are still far away, Yoshida can bear it, but once the passage narrows and the cockroaches are about 1 m away, it's too much and Yoshida flees. According to the narration, cockroaches in caves never see sunlight, so they're pale in color, white or amber-like.

On Ishigaki Island, in a probably unexplored cave found by an apprentice, Yoshida encountered creatures that drove them close to panic. The apprentice said there were lots of bees at the entrance and they couldn't go in, but bees didn't bother Yoshida, who charged in on momentum. Looking at the flat ceiling, it appeared spiky, like a kenzan flower frog. Looking closer, it was moving: the entire ceiling was covered in cave crickets. Without exaggeration, there were thousands of them.

Yoshida froze and quietly went back outside. Thinking that if someone went in, some would fly off and their numbers would drop, Yoshida sent the apprentices ahead. They advanced while screaming, then called back, "It's huge inside — this is totally unexplored, you've got to come!" Yoshida made a firm resolve that, as a cave explorer, there was no choice but to get over it, and went in, but even after two or three apprentices had passed through, the ceiling was still thickly covered with cave crickets. Moving forward in a low crouch, the crickets reacted and leapt out, hitting Yoshida's back. It felt like big raindrops hitting an umbrella. Yoshida held their collar shut to keep them from getting down the neck and could do little more than freeze; some bounced off the floor and hit Yoshida's face too.

In the video, Yoshida says they may never have been that tense in their entire exploring career. Having talked so much about panic, Yoshida thinks they panicked a little this time, and realized that when there are that many of them, humans really do feel revulsion and panic to some extent.

Asked why they've been able to keep caving for more than 30 years, Yoshida first answers, "Simply because I love it." But on closer analysis, there have been many times Yoshida wondered whether they truly love caves, and sometimes concludes they don't actually love caves all that much. So what does Yoshida love? What Yoshida can say clearly is, "I love the unexplored."

According to Yoshida, the only unexplored places left on Earth are the deep sea and the underground. The surface can almost all be seen on Google Earth. For explorers who seek the unexplored, there's nowhere to go but caves. Yoshida says that, having thought about it a lot recently, they've come to understand that this is the situation in which they're heading into caves. And if you pursue the unexplored to its end, it extends beyond Earth: caves have been found on the Moon and on Mars. The planets themselves are unexplored, and the holes on them are unexplored too — there's no end to it. Yoshida keeps on with an exploration that has no goal and can never possibly be completed. Is there anything equally exciting to replace exploring if Yoshida quit? No. So there's nothing to do but this — that's Yoshida's honest conclusion.

If you don't go near dangerous places, you won't run into danger. That's obvious, but Yoshida says life would be boring if that's all there were. To discover something new, it's important to move forward even at some risk; in any field, discovery requires challenge, and challenge always comes with risk. If you don't want to take risks, you can't take on challenges, and if you don't take on challenges, life becomes boring. Yoshida concluded that their team just happens to do this in caves, and keeps caving in order to live life joyfully and interestingly, and to discover things and be moved by them.

Finally, asked "What are caves to Katsuji Yoshida?", Yoshida replied, "It's no exaggeration to say they're my life itself." Going to caves has become a lifestyle and the center of Yoshida's life. And caves, as a medium, have brought many things into Yoshida's life. Yoshida sometimes wonders what life would have been like without caving, and thinks it would have been dull. When thinking about how truly fortunate it was to encounter caves, Yoshida's eyes well up and they nearly cry, Yoshida said.

As for retirement, Yoshida says it will be one of two things: dying, or the body becoming completely unable to move, causing trouble for the apprentices to the point they say, "Please, Yoshida-san, don't come anymore." Since Yoshida wants to keep going as long as they live, what they can do now is take care of their health and extend the time they stay fit. Within the past three years, Yoshida has gained apprentices who seem likely to carry on what Yoshida has done. Yoshida says they intend to keep exploring as long as their body allows, watching those apprentices grow and passing on all sorts of things to them.