
Come with us as we take you off the beaten path to a spot tourists are yet to discover.
While most people who visit Japan journey along the well-beaten path between Osaka, Kyoto and Tokyo, there’s a whole world of breathtaking sites and hidden discoveries lying outside these urban areas. Today we’d like to introduce you to one of these hidden sites, which is well-known to locals but still yet to be discovered by tourists, and it’s located well off the beaten track, tucked away in the mountain town of Misato in Kumamoto Prefecture, on Japan’s southern island of Kyushu.
With no train access, Misato can be accessed in about 30 minutes by car and 90 minutes by bus from Kumamoto City, and with a population of roughly 10,000, it’s a quiet, peaceful locale that’s best known for its historic stone bridges.
Toshinebashi Bridge, for example, is about 24 metres (78 feet) high, and was built in the Taisho period (1912-1926) to carry the main traffic on the prefectural road. It’s an impressive structure, particularly considering the number of stones used in its construction approximately a century ago.
We were interested in checking out another man-made structure while we were in the vicinity: the mysterious octagonally shaped Hakkaku Tunnel. Located off National Route 443 near the Toshinebashi Bridge, the tunnel is hidden from the main road with only a small sign at the carpark in front of the path leading up to it, written in Japanese.
It’s a 200-metre (0.1-mile) walk from this sign to the tunnel, and with nobody around as you walk the leafy mountain path towards it, you quickly begin to feel as if you’re walking through the home of magical creatures from a Studio Ghibli anime movie.
The comforting crunch of the leaves beneath your feet is all you’ll have to keep you company, and as the path narrows near the tunnel, things start to feel a little creepy.
As you walk around the winding path, the tunnel gradually begins to appear, presenting itself with a mysterious aura that causes your jaw to drop as you begin to take in its unique appearance.
Entering through the first octagonal opening feels like entering another dimension. Part sci-fi, part steam-punk, part fantasy game world, it’s not just the structure itself but the eerie stillness and the way the light hits it that makes it feel so otherworldly.
The tunnel is made up of seven octagonal rings, and walking through them makes you feel like you’re travelling in a time machine, creating a mixture of emotions ranging from awe through to fear, excitement, and exhilaration.
▼ Warping through space and time in the octagonal tunnel is a lot of fun.
Delving into the mystery of the structure reveals it was actually constructed back in 1915, when the Yuuen Railway opened in the area, running for a total length of 28.6 kilometres to Misato from what’s now known as Kumamoto City. Hakkaku Tunnel (Hakkaku translates to “octagon”) was designed to prevent rocks falling from both sides onto the railway, but the reason why it consists of seven unconnected octagonal arches is still a mystery.
There are several theories behind it, the most popular being that it was an attempt to reduce construction costs. It was abandoned when the railway closed in 1964, but now, 50 years later, it remains as a site for people to connect with the area’s industrial history.
We’ve yet to meet another tunnel with such a mysterious pull, and we highly recommend seeking it out whenever you’re in the area. The most memorable sightseeing spots are often those you have entirely to yourself, and we’re glad this one is out of the way to save it from being overrun with tourists and Instagrammers.
If adventures like this make you hungry for more off-the-beaten path discoveries, you might want to check out this otherworldly power spot and the edible insect vending machine, both also located in Kumamoto Prefecture.
Site information
Hakkaku Tunnel / 八角トンネル
Address:Kumamoto-ken, Shimomashiki-gun, Misato, Komushiro
熊本県下益城郡美里町小筵
Photos ©SoraNews24
● Want to hear about SoraNews24’s latest articles as soon as they’re published? Follow us on Facebook and Twitter!
[ Read in Japanese ]









Japan Travel: Explore a hidden cave on a tiny monorail roller coaster thrill ride in Nara
Japan Travel: Exploring Manabeshima cat island
We deeply regret going into this tunnel on our walk in the mountains of Japan
This mysterious tunnel in Japan is like none you’ve ever seen before
Japan Travel: Mysterious landscape found near a park with severed heads
Salomon releases Japan-exclusive Mt. Fuji hiking gear that doubles as an amazing souvenir
Japan triples departure tax, foreign tourists and locals now must pay more to leave country
Starbucks Japan teams up with Converse Tokyo for a new limited-edition collection in honour of Tanabata
Japanese overnight sightseeing train returns for summer with ramen stops and ocean views
Sanrio Character Poll announces winners, Hello Kitty absent from top 10 in many countries
7-Eleven Japan has a lot of famous food, but its new burrito needs to be on your radar
Studio Ghibli releases a musical diorama based on a touching anime scene from My Neighbour Totoro
Japanese train company brings back beloved “patapata” departure board…with a clever digital twist
One Piece docking at Round 1 amusement centers in both Japan and the USA
Live-action Spirited Away stage play announces world tour with first-ever U.S. and Canadian dates
Tokyo has only two barley tea makers, and we visited one to see how mugicha is made
Pikachu brings electric style to brand-new Pokémon G-Shock watch featuring every stater trio
Family Mart Japan installs red-eyed “Monster Wolf” to keep bears away from convenience store
Starbucks Japan reopens Shinkansen platform store after redesigning it for speed
Blind Tokyo commuter explains the easiest place for him to stand while riding the train
Japan announces sudden 400-percent increase in visa fees for foreigners entering the country
Japanese ninja certification exam attracts 131 candidates from Japan and abroad
Studio Ghibli store Donguri Republic announces opening of first-ever store in America
New Japanese overnight train coming to connect Tokyo with Tohoku in sleep-travel style
Japan launches first overnight Shinkansen bullet train between Tokyo and Osaka this summer
Even at twice regular Daiso price, this handy item is still great for summer travel in Japan
Japanese sweets shop sells an ohagi so exquisite it sells out by noon
Forget Tokyo go-karts – there’s a new way to sightsee on four wheels in Japan
Japanese sweets brand creates new drinkable Cigare and we’re totally here for it
Japan’s human washing machines will go on sale to general public, demos to be held in Tokyo
Starbucks Japan releases new drinkware and goods for Valentine’s Day
We deeply regret going into this tunnel on our walk in the mountains of Japan
Starbucks Japan releases new sakura goods and drinkware for cherry blossom season 2026
Japan’s newest Shinkansen has no seats…or passengers [Video]
Put sesame oil in your coffee? Japanese maker says it’s the best way to start your day【Taste test】
Japan reportedly adding Japanese language skill requirement to most common foreigner work visa
Japan’s 5.3 million beautiful Hitachi Nemophila flowers are now in full bloom[Photos]
Japan Travel: Mysterious rockstar Jizo statue found at Kiyomizudera temple
Japanese hand-dug tunnels on a bamboo forest trail are like a quest in a video game
We travel to a mysterious power spot in Okinawa, where a “heart rock” floats in the sea
Mystery Tourist Spot: Merlions in Japan?
Mysterious mountain village is home to Christ’s grave and an ancient pyramid
There’s something fishy about this mysterious tourist spot in Japan
Shimane’s hidden travel sites, where you can escape the crowds and enjoy traditional Japan
Ancient temple with National Treasures is a hidden gem on the Nara Yamato Four-Temple Pilgrimage
Chikura no Iwaya: Secret beach cave only appears for two hours a day, and here’s how to see it
Mysterious salt cauldrons predict disasters at one of the “Three Great Miracles of Japan”
Japanese airlines offer discounted fares to international tourists
Japan travel: Best places to see, eat and stay at Nagato and Mine in Yamaguchi Prefecture
Travel off the beaten path to a secret spot in Japan where bamboo grows wild on an old train line
World’s only double-helix wooden structure, Aizu Sazaedo, is mysterious both outside and inside
The Japanese train station with torii gates on its tracks
Japan travel: Best things to do, see and eat in Hagi and Yamaguchi City in Yamaguchi Prefecture