Posted: April 21st, 2010
Japanese SuperSub
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Browse images related to Secrets of the Dead: Japanese Supersub including photos of the original Japanese and United States naval crews, stills from animated renderings of the I-400 in action, and the final moment of surrender when the sub was captured.

  • Paul

    Where are the I-400 ships now?

  • Allen

    @Paul – They are at the bottom of the Pacific.

  • dave

    where are the aircraft..I missed viewing the episode and a full viewing was not available

  • Peter

    The submarines are actually located just off of Pearl Harbor in Hawai`i.

  • David Johnson

    They were taken off of Barbers Point in Hawaii. Considered one of the deepest areas. The Navy wanted to test the newest firing detonators for torpedos. This information was told to me by my Dad who served aboard the I-400 US crew when coming back from Japan..Check out

  • Roberto

    The video stated the Japs tossed all the airplanes overboard prior to surrendering to the US to hide the fact that they had painted the planes to look like American Aircraft. They were worried about repercussions as this is a violation of rules of war. What the heck they were already messing with biological and chemical weapons with intentions of using them on the US mainland (from video). They were also sending soldiers on suicide missions..
    What the show did not say was if all the I-400 planes were kept out of US hands. Pretty darn sophisticated.



  • Omar

    Treacherous Jap motherfuckers should have been burned alive.

  • Tom

    Written July 21, 2010: I am 64 years and I was not born until after the WW-2 ended in 1945. I was born 1946, which is known as a WW-2 Baby Boomers. However, I have never heard about this Jap Sub, until today when I saw the movie on TV. (Channel 24 Orlando, Florida). I can only wonder why it was kept such a secret so long? Anyway, I was amazed. I also saw a movie not too long ago about how Hitler wanted to use Britain as a jumping point for his future attack to concur the USA,. Again, I never saw any like this. I guess in the 1950’s -60’s growing up, my generation was kept in the dark. I can only wonder now – “What else has been hidden from the Public form past Wars, and let’s not forget the present Wars? Anyway, I wish to thank this TV Station for showing these films.

  • Thomas b

    Wow those were awesome subs!….too bad they just didn`t hide them at Pearl instead of blowing them up…….Even though they were the Enemies,Japan and Germany,they had some great weapons.Lot of smarts there,too bad they used it to try and rule the World…….watch the episode on the Yamato Battleship!,that was a fantastic ship that never got to do much either…….we all learned from their technology.

  • Roy Boone

    There is an excellent book out on the I-400 written by Henry Sakaida, Gary Nila and Koji Takaki, published in 2007 by Hikoki Publications.


    This is a great site, I was wondering if anyone would have any intrest in acquiring the collection of I 400 relics that I have come across. It is quite a thing to see. Best Regards.

  • Dwayne

    Yeah, right–’f’ them. Pearl Harbor cost the US around 3000 lives, mostly military (although some civilians). Before the war ended the USAAF killed HUNDREDS OF THOUSANDS of Japanese civilians via atomic and fire bombs. Isn’t that punishment enough? Get over it…

  • Gary T

    Understand the subs were sunk following our ‘inspection’ to prevent sharing the technology with Russia.

  • Scott T

    Interested in the sonar absorbent hull coating and the airplane engine pre-heaters that were mentioned as being ‘borrowed’ from the Germans. A technology transfer between Germany and Japan, in war time, would have been challenging to say the least. Does anyone know more about this? Especially the hull coating which was described as being “still classified”.

    I know the Germans tried gluing rubber sheets over the hull of a couple of U-boats, but could not find an adhesive that would permanently bond these sheets to the hulls while exposed to salt water. And, at best, these coatings absorbed 10-15% of the sonar beam. The way the I-400 coating was described made it sound much more effective.

    I am aware of ‘rumors’ that Ju-390s (6 engined ultra-long range transports) flew from the Ukraine to Manchuria during the period of time when the Germans controlled that part of the USSR. I think there also were a few successful submarine voyages between German-controlled Europe and Japanese-controlled Asia. But it is difficult to imagine that a handful of airplane and/or submarine transits would support the sort of large scale technology transfers necessary to design and build the I-400.


    Lastly – what’s up with the slurs anyways? Have some class…

  • Ken

    A Seiran is on display at the Udvar Hazy museum by Dulles airport

  • Ken M

    I saw one of these subs at Pearl Harbor. I enlisted in the navy as a reserve in 1945.
    The atomic bomb was exploded in Japan while I was in basic training (Great Lakes )
    I was assigned duty in the Phillipines in 1945. I shipped out in dec 1945 on an Atr . The Submarines
    were in route to Pearl Harbor slightly earlier than we were . I then was assigned to duty on an ARD
    at the Sub Base at Pearl Harbor . The base was preparing for the Bikini bomb test collecting all types
    of ships. The I 400 and I 14 had arrived at “Pearl” . I was amazed when I saw them at dock .They
    were a lot larger than our std submarines plus they could carry launchable planes that could be
    catupulted. A memory that I will not forget !!

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