Fortress port of Yokosuka

The city of Yokosuka is one of the major cities of Japan, and it is well-known due to having the only active Naval Academy in the country. The city is located on the shores of Yokosuka Bay a few miles to the south-west of the splinter capital Tokyo and is surrounded by a fortress wall from the sea side.

Yokosuka Port Fortress wallEdit


The wall around the Yokosuka bay while still under construction

Originally, seventeen of the most important ports in Japan were supposed to have their bays protected by citadel walls. However, the shortage of resources forced the government to rethink, and the port of Yokosuka city became the only place where the construction of such wall was complete.

Even then, the construction of something of this gigantic scale took years. The construction of the wall began sometime before the Great Battle of 2039, but was completed only between 2054 and 2056 - it was shown that I-401 with Gunzou inboard slipped through the gap in the wall when they first left Yokosuka in 2054.

The fortress wall completely surrounds the Yokosuka bay, creating an enclosed space big enough even for some minor naval maneuvers. The vessels that want to enter or leave the bay have to pass through colossal gates installed in the wall. The total number of these gates is unknown but it is presumed that there are at least seven of them.

Underwater, the fortress wall has huge vents installed at regular intervals; these vents are needed to smooth the sea currents around the wall on the outside, but they are create rather complex and often hectic underwater currents on the inside. This allowed the I-401 used these currents to her advantage during her battle with battleships Haruna and Kirishima (both manga and anime)

Even though an incredible amount of resources and time was spent on construction of the fortress wall surrounding the Yokosuka bay, the wall itself proved to be quite ineffective as it barely slowed battleships Haruna and Kirishima when they attacked the city in an attempt to sink I-401.

Yokosuka PortEdit


The port of Yokosuka

Within the relative safety of the fortress wall lies the port of Yokosuka city. While the number of active vessels isn't very big at this time, a group of military patrol boats is stationed there. While it was never confirmed, it is quite possible that civilian ships - like fishing trawlers - are present there as well.

Yokosuka port is mostly notable for its shipyard - the only known shipyard in Japan that didn't cease working after the Great Battle against the "Fleet of Fog" in 2039. Hakugei class submarines were constructed and are serviced at the Yokosuka port shipyard.

Fortified underground dry docksEdit


Fortified dry docks in Yokosuka port

Yokosuka fortress port has four fortified underground docks, each with the capacity to store up to twenty battleships. A significant portion of the Japanese Navy vessels that have survived in the great Battle against the "Fleet of Fog" in 2039 are stored in these dry docks.

When I-401 visited Yokosuka in 2056 in order to collect the blueprints and the prototype of the Vibration Warhead Torpedo, she was placed in one of these dry docks. However, due to her nature as the "Fleet of Fog" vessel, not all of the damage she had sustained in her battle against the heavy cruiser Takao could be repaired by the humans.

Submerged cityEdit


The old and submerged Yokosuka city

When the sea level began rapidly rising at the beginning of the twenty-first century, the old city of Yokosuka became submerged. Right now, in 2050s, it can be seen as underwater ruins.

During her battle against the battleships Haruna and Kirishima, I-401 used this submerged city in order to hide from her opponents' active sonars. In manga, Hakugei (3) submarine used similar tactic as well.

In manga, it is also said that I-402 used to visit the places like this from time to time in order to collect interesting human-made trinkets.


The husk of battleship Mikasa in the submerged Yokosuka city

Within the old and submerged Yokosuka City, there used to be Mikasa park - a park in which the decommissioned in accordance with the Washington Naval Treaty battleship Mikasa was preserved as a museum ship.

In the anime, the husk of battleship Mikasa was used by I-401 twice during her battle against the battleships Haruna and Kirishima. The first time, I-401 had covered the husk with active nanomaterials in order to confuse the battleships and give them the false target. The second time, an semi-automatic torpedo launcher was hidden in the shadows of Mikasa. This launcher eventually launched the Corrosive Warhead Torpedo that destroyed both Haruna and Kirishima.

Japanese National Maritime Institute of TechnologyEdit


Japanese National Maritime Institute of Technology

Yokosuka city is well known as the biggest naval base in Japan after the Great Battle against the "Fleet of Fog" in 2039. Thus, it is not a real surprise that the best and, quite possibly, the only naval academy in the country is also located in Yokosuka.

This academy is the Japanese National Maritime Institute of Technology. It trains the future naval officers of Japan that, one day, may let the humanity once again sail across the seas; but right now, the graduates of the Institute can do little more than preserve whatever naval traditions are still intact.

The Institute makes use of several training facilities that belong to Japanese Navy. In particular, the facilities #4 and #18 are mentioned in the manga. Facility #4 is mostly well known thanks to the terrible fire that had happened here in 2054 and had claimed lives of 66 Institute's students.

Most notable students and alumna of the Japanese National Maritime Institute of Technology are:

  • Chihaya Gunzou - The current captain of the "Fleet of Fog" submarine I-401. He had run away with I-401 in 2054 and, thus, had never properly graduated from the Institute.
  • Amaha KotonoChihaya Gunzou's childhood friend and one of the students that died during the Facility #4 fire. Her death, apparently, was the last straw for Chihaya Gunzou, and when he was approached by I-401, he agreed to run away from Yokosuka with her. While it is not confirmed yet, it looks like Kotono was and still is one of the supreme flagship Yamato's Mental Models.
  • Hibiki Maruri - The original sonar operator on I-401 under Gunzou. Currently, she serves as the advisor on all matters related to the "Fleet of Fog" inboard of Hakugei (3). She had returned to the Academy sometime in 2055 and had graduated with the rank of ensign.
  • Oribe Sou - The first mate of I-401 under the captaincy of Chihaya Gunzou. Ran away from the Institute in late 2054 or early 2055 and, thus, had never properly graduated.
  • Watanuki Iori - The engineer inboard of I-401 under the captaincy of Chihaya Gunzou. Ran away from the Institute in late 2054 or early 2055 and, thus, had never properly graduated.
  • Kashihara Kyouhei - The man in charge of weapon systems inboard of I-401 under the captaincy of Chihaya Gunzou. Ran away from the Institute in late 2054 or early 2055 and, thus, had never properly graduated.
  • Vice-admiral Uragami Hiroshi - The officer in command of the Military Command's Naval Strategies Office. He had graduated from the Institute some time before the Great Battle against the "Fleet of Fog" in 2039. While it was never confirmed, it is possible that he also taught there at some point.
  • Komaki Daisaku - The captain of Hakugei (3) submarine. He had graduated from the Institute some time after the Great Battle against the "Fleet of Fog" in 2039; it is possible that vice-admiral Uragami Hiroshi was one of his teachers in the Institute.
  • Iona, the Mental Model of I-401 - Infiltrated the Institute in 2054.
  • Takao - Her Mental Model is currently posing as one of the Institute's students on supreme flagship Yamato's orders, apparently, in order to prevent Haruna and company from finding certain things about the Facility #4 incident.
  • Haruna-infiltrated the Institute on orders of the Prime Minister of the Northern Region to investigate the Facility #4 incident. Unlike Takao, she was properly accepted into the Institute on the recommendation of the Northern Region.
  • Kirishima-Haruna's teammate. Haruna has to keep Kirishima close at all times since Kirishima was stuck in a teddy bear outfit. Also infiltrated the Institute with Haruna. Thanks to her teddy bear outfit, nobody (inside the Institute) has managed to recognize her (yet).

Warehouse 51Edit

I-401 dry dock

Captured I-401 in dry docks

Warehouse 51 is one of the dry docks of Yokosuka port. It is notable because the "Fleet of Fog" submarine I-401 was stored there in 2046 - 2054, following her return to Yokosuka port without her original human crew under the command of captain Chihaya Shouzou.

In 2054, sometime after the Facility #4 fire, I-401 reactivated seemingly on her own and broke free from the dry dock she was stored at. She then chose Chihaya Gunzou as her new captain and the two of them ran away from Yokosuka.

It is also known that I-401 has been brought to Yokosuka after her capture during the Great Battle of 2039, but it is presently unknown, where exactly she was stored between years 2039 and 2045.

Osakabe MansionEdit


Osakabe mansion

Osakabe Mansion is a mansion on the outskirts of Yokosuka city. It was given to the scientist Osakabe Toujirou, the head of the Design Children project, in order to "store" Design Child Osakabe Makie after she had successfully finished her task - development of the Vibration Warhead.

When Makie came in contact with the "Fleet of Fog" battleship Haruna's Mental Model, the mansion was besieged by the Japanese Army in order to kill Makie and prevent the "Fleet of Fog"  from obtaining the data on the Vibration Warhead. The operation was actually a success because, although Makie isn't dead, Haruna didn't share any data on the Vibration Warhead and ever since then the mansion stands abandoned.



Yokosuka city cemetery

Yokosuka City Cemetery is also located on the outskirts of the city, apparently not that far away from the Osakabe Mansion. On this cemetery there are beds of honor for those who have died in the Great Battle against the "Fleet of Fog" in 2039. In anime, there is also a memorial for these navy men in the cemetery.

In the manga, the cemetery contains another memorial (though very similar in design) - for those who had perished in the Facility #4 fire. It was from this memorial that we learned the name of Amaha Kotono.

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