
There’s one level in this underground dungeon that can only be seen, but not accessed, by the public.
“There’s something that’s been bothering me on my commute, so could you please look into it?”
That was the message our Japanese team received from a reader recently, and it immediately piqued our interest. The message went on to reveal that at Korakuen Station in Tokyo, on the way from the Marunouchi Line to the Namboku Line, there’s an elevator with a button for a floor labelled as “B3”. Due to the setup of the station platforms, however, the floor doesn’t seem to make sense, but with the reader feeling too timid to press the button, they asked our team of reporters to investigate.
▼ So we headed out to Korakuen Station to visit the mystery floor.
After arriving, we walked along the Marunouchi Line platform, where we noticed a wall mural that resembled a castle from Dragon Quest. This seemed like an apt artwork for our adventure, but it also made us fear that difficulties and dangers might lie ahead.
Japanese train stations are so vast they’re often referred to as dungeons, and this mural seemed to be challenging us to push through to the final stage, defeat the boss, and rescue the princess.
▼ Feeling emboldened, we scanned the signboard and headed to the elevator.
▼ It didn’t take us long to reach the lift, which looked like any other ordinary elevator.
The Marunouchi Line is located on two above-ground floors, while the Namboku Line is located on six underground floors. With a difference in elevation of approximately 41 metres (134 feet), these are two of the largest subway lines in Tokyo.
Stepping into the elevator on the B1 level, we looked at the control panel, where we saw buttons for B1, marked “改札階” (“Ticket Gate Floor”), B5 (“都営線連絡階” [“Toei Subway Connecting Floor”]) and B6 (“ホーム階” [“Platform Floor”]). This was the same as the floor listing on the sign posted outside the lift when he got in, but inside, there was also an unmentioned “B3” level, which unlike the other levels, had no explanation next to it.
Finger quivering, we reached out to press the B3 button. However, after pressing it, it refused to light up, and what’s more, it triggered an announcement, with a calm-sounding pre-recorded voice saying: “No stopping on that floor”.
With other passengers in the elevator, the announcement hung in the air, creating an awkward moment. We could feel everyone’s eyes on our back, as if they were wondering why we’d pressed the button, but our embarrassment was soon forgotten as the lift began its descent.
▼ Camera poised to capture images of the mystery floor, we shot this video of the B3 level.
As indicated by the announcement, the elevator didn’t stop on this floor, and from what we could see of it, it didn’t appear to be intended for public use. Although it was brightly lit, there was no sign of life there, making it seem like a foreboding area in a zombie game, where the undead might burst through the door at any moment.
Looking closer at the sign on the door reveals the reason for its existence, as we could make out the words “変電設備” (“Electrical Substation Equipment“). Substations are facilities that convert high-voltage electricity sent from the power company into a voltage that can be used at stations and on trains, so the B3 level appears to be dedicated to equipment that supports the underground workings of the station. Stations consume a huge amount of electricity, running the subway, operating the lights and escalators…and the beating heart of it all is housed on the mystery B3 floor.
While ordinary members of the public aren’t able to access this level, it does need to be accessed by maintenance workers, who likely have a way of bypassing the normal controls, either through a special key, code or prior permission from station staff, hence the existence of the B3 button.
Being able to see, but not access, the floor does give it a mysterious allure for people using this lift. It’s just one of the many mysteries you’ll find inside Japanese train stations, like the secret stairs at Tokyo Station.
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 ]










Tokyo station becomes first in the city to install an inclined elevator
The golden escalator hidden at a Tokyo train station
What are these strange empty “seats” that are being spotted in Tokyo train stations?
Doai Station: The deepest station in Japan is also one of the scariest, like a video game dungeon
The cool secret hidden in Tokyo Metro pillars at Ginza station
7-Eleven Japan now has ramen machines…but only at 41 stores
Tinder just opened a convenience store in Japan, aimed at adults only
“Disaster”: 2018 Kanji of the Year unveiled by Buddhist monk at Kiyomizudera temple in Kyoto
Secret staff cafeteria in Tokyo is a hidden gem you won’t find in travel guides
“They’ve got be kidding me.” – Mayor in Japan fed up with off-season Mt. Fuji hikers needing rescue
Man tells Nintendo HQ “I’m going to blow you all the hell up,” gets arrested by Kyoto cops
Starbucks Japan adds a new Frappuccino and Milk to the menu, but are they worth the calories?
“Hey, Japanese taxi driver, take us to the best seafood restaurant in Noboribetsu!”
New bounty system starts in Japan, rewards reports of illegal employment of foreigners
Japan’s Kanji of the Year announced, shows the bright and dark spots of 2024【Video】
Japan now has gyoza doughnuts, and they taste like no other doughnut we’ve tried before
Starbucks Japan releases two new “chunky” drinks… and matching gel designs for our nails
Mt. Fuji hot spring inn gets even more beautiful after dark with Firefly Festival
Does one of Japan’s favorite chocolate brands work with the Pringles chocolate hack?
Japanese criminals are now using crabs to hunt for burglary targets
Japan releases new ramen sandwiches… that don’t taste like ramen
Japan enters Golden Week vacation period, survey shows one in three plan to ride it out at home
Japanese Pokémon card shop grabs scissors as part of its plan to keep scalpers away
This train station bento boxed lunch shop has been in business for nearly 100 years
The average age of Japan’s hikikomori shut-ins is getting older, survey shows
Japan’s 5.3 million beautiful Hitachi Nemophila flowers are now in full bloom[Photos]
Wisteria season starts early with blooming of Japan’s Great Wisteria in its beautiful garden
New Kyoto Converse sneakers celebrate Japan with traditional kimono fabrics for your feet
Brand-new Pokémon manhole covers coming to help the recovery of a disaster-stricken part of Japan
Japan’s awesomely beautiful Alpen Route snow corridor is now open
Japan’s best conveyor belt sushi restaurant of seven years ago has now, finally, come to Tokyo
Japan’s new Pokémon jackets give you the look and powers of the Kanto starter trio
Injuries on stairs in Tokyo highlight an overlooked design flaw
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]
Major Japanese hotel chain says reservations via overseas booking sites may not be valid
Put sesame oil in your coffee? Japanese maker says it’s the best way to start your day【Taste test】
No more using real katana for tourism activities, Japan’s National Police Agency says
Japan reportedly adding Japanese language skill requirement to most common foreigner work visa
Secret stairs at Tokyo Station dungeon come with a serious warning
What’s the real reason for the ‘floating’ 3-D signs at Haneda Airport?
Stay in a special Tokyo Metro train room at a hotel with a front seat to the railways
Tokyo farewells Japan’s only double-decker Shinkansen with a special escalator at the station
What is this weird train spotted at a Japanese railway station?
Japanese pizza chain opens stand at Tokyo station platform
Act of Japanese kindness touches one man’s heart, provides hope for elevator etiquette
Secret staff cafeteria at this Japanese train station is still open…for those in the know
Train otaku say this is the narrowest train station platform in Japan
How to cancel a floor on a Japanese elevator
Fossil of an extinct crab discovered in a pillar at Tokyo Station
The Japanese train station famous for mysterious dancing cats
Tokyo Station’s second-most popular bento is great because of what it isn’t【Taste test】
Tokyo Station Waterscape Toilet looks more like an aquarium than a bathroom
What to do if your phone battery dies when using a mobile transit pass on a Japanese train
This ekiben train station bento is filled with surprises