Kaze no To and Umi Hotaru, Tokyo Bay

Mike GristHaikyo, Tokyo-to, Vaults 19 Comments

From the 25th floor lobby of the Dentsu HQ in Shiodome there’s an awesome view across Tokyo Bay, taking in Hamarikyu gardens, Odaiba, the Rainbow Bridge, and in the distance, fogged by pollution and heat distortion- a weird-looking dome-shaped structure out in the middle of nowhere.


Weird dome, at 200mm zoom from the edge of Odaiba.

What is this bizarre structure? I asked several of my students, and none of them knew. One of them guessed it was the Pan Plaza Hotel in Yokohama, but most weren ‘t even sure if we were looking at Yokohama or all the way over to Chiba.


From the edge of Odaiba with a little zoom.



From Dentsu 25th floor, the dome between Fuji Terebi (on the right) and some other buildings on the left.

My curiosity piqued, I went on the web to hunt this thing down, resorting to scouring the line of sight on Google maps from Dentsu across Odaiba between Fuji Terebi and other buildings.

Line of sight from Dentsu all the way to Chiba.

I started off searching the Chiba coast, looking for a big circular dome perhaps affixed to a power plant or town center. But- nothing. So on a whim I spread the search down the line into Tokyo Bay, and BAM, found it.

What are these things?


Zoom in and we see the dome from above, actually 2 ovoid domes on a circular platform. Is this some weird kind of art?

On the zoomed in googlemaps shot I could read the kanji- which says 風の塔, kaze no to- or ‘Tower of Winds’.

That sounds awesome- like something out of a Miyazaki movie: the Lilliput floating castle, the mythic bath-house in Sen to Chihiro, the Tower of Wind.

I image searched and came up with these:

From a helicopter- looking great.


Gorgeous shot from the waterline.

The white dome bits.

Wikipedia gave the low-down: The Tower of Wind is a ventilation shaft for the Tokyo Bay Aqualine- the world’s longest undersea tunnel for cars, which cuts under Tokyo Bay from Yokohama to Chiba. It’s 9.6km long underwater, took 31 years to build, cost 11.2 billion dollars, and shaves some 100km off the round the Bay trip to Chiba. It opened in 1997 but hasn’t yet reached traffic capacity- probably due to the hefty Â¥3000 ($30) fee to cross it one way.

Don’t get me started on road tolls in Japan.

A shot from the Umi Hotaru.

So what is the Umi Hotaru? It’s the bridge section of the Aqualine, about 5km long, and looks like an aircraft carrier affixed by a road to the Chiba mainland. Umi Hotaru means ‘sea firefly’, again a great name for a Miyazaki movie- so named because that’s what it looks like. I’ll let you make that determination for yourself:

Sea Firefly? (Image thanks to Mike at Mike’s Blender)

Helicopter shot, Sea Firefly sea airport.

I’ve never been to the Sea Firely myself, having rarely been to Chiba, and not having a car myself. My buddy Mike went there en route to picking mikans in Chiba a few months back, and reported it wasn’t up to much.

This is much nicer. I lost the attribution link- will happily add if anyone knows where it’s from.


Location – Tokyo Bay

Entry – Not to the Kaze no To, but yes to the Umi Hotaru.

Facts – Completed in 1997, took 31 years, cost $11.2 billion, longest undersea tunnel for cars at 9.6km.

Highlights – The hunt.


You can see all MJG’s Tokyo content here:

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Comments 19

  1. I’ve been through it a few times, back when I had a girlfriend who lived out in the Chiba countryside. But each time was on the bus, so we never stopped. Apparently they do a big fireworks show off of it on New Years, or maybe it’s a summer festival. Maybe worth checking out if you have 4 people to cram into the car.

  2. See, I love Google for stuff like this. Let’s you take short little adventures from your chair.

    I prefer real adventures of course, but hey, you’d never see stuff like that unless you had a helicopter and a boat!

  3. Surprised your students did not know. I would think that would be a very well known landmark in the Tokyo area. Also surprised they thought it might be the Pan Pacific hotel in Yokohama as if the Landmark tower suddenly disappeared.

  4. Very cool find, definitely Miyasaki-esque, though I’m a little disappointed that it’s not a futuristic ancient robot hotel ^^

    A friend of mine lives in Chiba, I’ll try to get her to go as close as possible to take some pictures.

    Nice one!


  5. Hello,

    I found out about the Tower of Wind all right – but what are the two floating structures to the right and left of the tower?
    I asked my students to find out as well, but without success, so far. Looks like fishing nets or sth like that to me, but does anybody know??
    Please help!! I’m dying of curiosity.


  6. Post

    Brian- Well, my buddy Mike who stopped there on a bus tour said it wasn’t up to much. I would’ve gone if easy[- to get better shots of the Tower of Wind- but now that I’ve made the post there’s no need.

    Lee- Definitely, a whole different kind of exploration, in comfort.

    Freedom- Cheers.

    Jean Rob- Hmm, I guess you could see the Sea Firefly, but I imagine it looks just like a bridge from the side. Maybe a nice city view? But not really- mostly docks and industrial cranes.

    Tornadoes- Most people don’t know, it’s not an easily seen thing- you have to be looking for it.

    Hao- Cheers, and I think it’s quite far from the Chiba side- the closest location for shots would probably by Kawasaki- or of course the Sea Firefly itself.

    Michael K.- Two floating structures, good call, I guessed nets to break rough tides, or something for stabilization, but just guesses.

  7. To MJG,
    thanks for your quick response and suggestions. I would rule stabilization out, as the tower itelf has a foundation some 40 metres deep into the seabed (according to a cross-section of the Aqualine I found elsewhere on the internet). As for nets against rough tides – why only on two sides and not all around like at the Sea Firefly? Anyway, thanks so far and maybe somebody nows anybody in the Tokyo area to clarify the options?! – Michael

  8. That’s one of the craziest things. Like it just ends in the water, it’s like a portal or something. I don’t know how to describe it, it’s a sort of unnerving but awed feeling I get looking at the road just vanishing into the sea. Nice Find indeed.

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  10. To MJG,
    another possible piece of the puzzle: meanwhile I found an interesting article on Aquaculture. The structures shown there are very similar to the ones at the Tower of Wind and only slightly larger – but I couldn’t find any information on aquaculture in that part of the Tokyo bay, so I’m still hoping for inside information by locals or travellers – unfortunately it is a bit far from Germany so I can’t just pop around the corner to see for myself…

  11. The large triangular shaped objects to the NE and SW of the platform are collision barriers, similar to what you will find hear bridges where there is significant water traffic. It helps keep large vessels from running into the platform along the normal direction of travel.

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  13. Pingback: Boyou Hotel Haikyo- Demolished | michael john grist

  14. Great article and photos! By the way, I am an ESL online teacher and one of my students is a Japanese engineer named Shinichi Kudo, who actually helped plan and also worked on the Tokyo Bay Aqua-Line project – especially on the Kawasaki Man-Made Island — until its completion in 1997!

    His stories and personal experience in regards to this amazing engineering feat are absolutely amazing! You can find part of his story — with actual pictures of the construction — online in my English_For_You Web Magazine on WordPress published today, 25 August 2014! Just Google! Happy reading!

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  16. Yeah I remember always seeing this thing out in Tokyo Bay and never being able to figure out what it was. It was just at the edge of my vision, couldn’t make out much and like your students at first thought it was the hotel in Yokohama.

    It was only after taking that route along with a couple friends to get to Chiba for a Martial Arts seminar that I found out what it was and more importantly what it was connected to and why.

    There’s also some similar structures in Odaiba as well as in Oi where the Wangan-sen goes under the water. And it’s funny, those made us think of something out of a Miyazaki movie as well. You can see one of them here: http://www.tptc.co.jp/cms/corporate/common/pages/c_park/01_03/shiokaze-009.jpg

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