We deeply regret going into this tunnel on our walk in the mountains of Japan

SoraNews24

07-07-2025

Seiji's stroll in Okutama takes a dark turn.
With a fierce heat wave hitting east Japan, our Japanese-language reporter Seiji Nakazawa had the idea to flee to the coldest place in Tokyo that he could find. That escape plan was a success, as you can read about here, but it was on Seiji's trip back that he ran into trouble.
To recap, Seiji's quest for the cold had taken him to Nippara Limestone Cave in Okutama, at the northwestern edge of the Tokyo city limits. The cave is located high in the mountains, and getting there requires first a train ride out to Oku-Tama Station, and from there a bus ride to the Shonyudo bus stop, from where it's another 10 minutes on foot to the mouth of the cave.
After emerging from his soothingly cool subterranean sojourn, Seiji retraced his steps back to Shonyudo bus stop, only to realize that he now had a very long wait for the next bus back to Oku-Tama Station.
As shown on the timetable above, there are only five buses a day on weekdays from Shonyudo, at 8:50 and 10:55 in the morning, and at 1:11, 2:38, and 4:11 in the afternoon (and no buses at all on weekends). Seiji had just missed the 2:38 bus, which meant that it'd be more than an hour and a half until the next one.
So rather than stand there and veg out, Seiji decided to go exploring.
There aren't many other tourist attractions near the cave, but the nearby neighborhood of Nippara has a cool vibe to it. It's a very small rural community, but the wooden buildings and faded signage make it feel like you've wandered into a pocket dimension where time stopped moving 50 or 60 years ago. In the light of an early summer late afternoon, the scenery takes on an especially nostalgic glow.
As a matter of fact, the atmosphere was so pleasant that before he knew it, Seiji had walked all the way to a different bus stop, Higashi Nippara.
Seiji could see that he would still have to sit and wait for quite a while until the next bus came by. However, there was also a local area map posted at the bus stop, and giving it a quick glance, Seiji was surprised to see that he'd already made what looked like quite a lot of progress towards Oku-Tama Station.
▼ Shonyudo bus stop (yellow), Higashi Nippara bus stop (green), and Oku-Tama Station (blue)
So once again, instead of twiddling his thumbs, Seiji made the decision to move his feet, and figured he'd just walk the rest of the way to the station.
Right away, this felt like a great plan. Not to knock the exciting stimulation of big city life, but for a guy whose apartment is in Shibuya and whose office is in Shinjuku, two of the busiest and most crowded parts of Tokyo, all of this tranquil greenery was a very welcome change of pace.
But another change of scenery was waiting for Seiji when he reached the Nippara Tunnel.
This is a 1,100-meter (3,609-foot) corridor through the mountains, but since Seiji had already spent part of his day underground, and had been walking for a lot farther than 1,100 meters to get here, he figured it'd be no sweat making it to the other side, so in he went.
It didn't take long, though, for Seiji's mental state to change. The tunnel is long and curved enough that you can't see the other side as you enter, and as you advance, the light from where you came in gets dimmer and dimmer. If you're in a car, your headlights will make sure the area around you is always illuminated, but on foot, the pools of shadows between the sparse interior lighting grow darker and denser the further in you go.
Making things even creepier, a constant deep, dull rumbling began to fill Seiji's ears, but looking around, he couldn't find its source. It turned out to be the noise made by cars driving in other sections of the tunnel, but with it being so long, you can hear the sound even when the vehicles are nowhere to be seen, making the reverberations freakily unsettling.
Seiji was now so far into the tunnel, though, that turning around and going back the way he'd come probably wasn't going to get him out of there any more quickly than soldiering on, so he took a deep breath and pushed forward.
And then, finally, he saw the literal light at the end of his tunnel ordeal.
Basking in the liberating sunlight, Seiji glanced at his watch and saw that he'd been in the tunnel for 10 minutes. Psychologically though, he felt like he'd been in there for two hours, what with how the anxiety had warped his sense of time.
This wasn't Seiji's only time-based surprise on his walk, either. Remember how when he checked the map way back at Higashi Nippara bus stop he'd thought he'd already walked half-way from Shonyudo to Oku-Tama Station?
▼ Again, here are Shonyudo bus stop (yellow), Higashi Nippara bus stop (green), and Oku-Tama Station (blue) on the map.
Well, it turns out that map isn't drawn to exact scale. On foot, it's about 20 minutes from Shonyudo to Higashi Nippara…
…but from Higashi Nippara, you've got 1 hour and 45 minutes more walking to do before you get to Oku-Tama Station.
In the mapmakers' defense, the map does list the amounts of time (by bus) from one stop to the next, and if Seiji had bothered to do some quick arithmetic, he would have noticed that the combined times from Higashi Nippara to Oku-Tama Station are a lot longer than the total from Shonyudo to Higashi Nippara. Or he could have paid attention to the text at the bottom-left of the map, which says that the total bus ride from Higashi Nippara (東日原) to Oku-Tama Station (奥多摩駅) takes 30 minutes, and that the ride from Shonyudo (鍾乳洞) to Oku-Tama Station is 35, just five minutes more, which is another clue that Higashi Nippara isn't anywhere close to the midpoint.
▼ Granted, the way this is presented is a little unusual, since ditto marks are rarely used in Japanese, but still, the information is there.
▼ The whole walking route from Shonyudo to Oku-Tama Station via Higashi Nippara
So yeah, even though buses are pretty infrequent from the cave, there are two good reasons Seiji didn't see anyone else trying to walk back to the station. That's not to say it's not a doable little adventure, but if you're going to try retracing Seiji's path, you'll want to make sure you've got comfy shoes and strong nerves.
Photos ©SoraNews24
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