History Fridge / ArpeggioOfBlueSteel

* The fact that I-401 is carrying around a WaveMotionGun normally reserved for at least heavy cruisers (hers came from a battleship, even) became less of a surprise if you dig around a bit in Wiki/TheOtherWiki. The I-400 class of Japanese subs are the largest submarines of the WWII, and continues to be the largest subs ever built until the Soviets build their nuclear-powered behemoths in the [=1960s=]. They are capable of circumnavigating the globe ''one and a half'' times on a full tank of fuel, and actually closer in concept to a submersible ''aircraft carrier'' (granted, their planes are ambhibious). Couple that with the advanced powerplant Fog Fleet has and the fact that 401 doesn't have any planes with her, that means there is enough room and power to store and (barely) operate the WaveMotionGun.

** The manga throws a wrench in this during the I-401's battle against the Kongou. It still has its aircraft complement, and it gets used.
*** Iona doesn't ''need'' to have the Seiran on standby at all times; she could've have assembled them from nanomaterials on-spot.

** Also the fact that, well, she doesn't really wear much under it to begin with until later into the story.
** This trait is anime-only and [[CharacterExaggeration an exaggeration]] of her first meeting with Makie when Haruna was disorientated and out of her depth. She's worn the coat less and less as the manga has progressed.

** [[BluntYes Yes]]. That is exactly what happened, there's no "fridge" aspect to it. [[spoiler:I-400]] was killed outright by that torpedo hit, and then immediately after, [[spoiler:I-402]] was killed when she sank below crush depth.

** China was discounted as a producer of harmonic torpedoes because it was devoting resources to intervention in the European conflict. Continental Europe (including Russia) is busy setting itself on fire in an unusual repeat of UsefulNotes/WorldWarI while Britain is even worse off than Japan (somehow). It's pretty much America or nothing.
*** This is still no answer, why they don't go to Sakhalin and from there, after crossing continental Russia, continue via the Bering Strait (which is frozen occasionally and thus can be crossed without even using ships) or the North Pole to the U.S.
*** There exists no infrastructure. The roads up past Mongolia are poorly maintained, and sometimes don't even have bridges. Eventually, there are not even any roads period, so it is literally impossible to get there. Even if you did, you'd still need to get a ship to the Bering Straight anyways, and then what would be the point at all?
*** Also note that with the exception of China and Russia (both discounted as explained above), America is the ''closest'' country able to produce the weapons.
*** Keyword from the backstory is Climate Change and as we know it today the North Pole freezes less and less and rising sea levels might contribute to the Bering Straight not being the shortcut you think it might be.

** The 20 meter rise in sea levels that feature in the backstory are notably absent from the London scenes: Chihaya Shouzou and Musashi have a conversation in London's Hyde Park, which is low enough in elevation for their park bench to be underwater at high tide; Buckingham Palace would be entirely flooded even at low tide.
** The Channel Tunnel linking Britain and France should still be running. Both terminals are either above the 20 meter waterline or could easily be protected from water. There's no reason the two nations wouldn't be connected unless the Fog deliberately destroyed the terminals (which goes against their general ban on attacking land targets) or if one or both countries cut ties deliberately (equally unlikely given the volume of trade that goes through, a naval/air blockade would make the tunnel of vital importance).
*** Unless the Fog destroyed the underwater portion of the Chunnel, but that would require drilling though around 45 meters (148 feet) of seabed to reach.

* [[spoiler:Judging from the imagery from the mental chatroom in episode 11 and the fact that the Corrosion Torpedo hit on 400's sail/fin (thus most likely hitting her right ''on the control room'')... ''Did Gunzou just obliterated 400's core?'']]

* The fact that I-401 is carrying around a WaveMotionGun normally reserved for at least heavy cruisers (hers came from a battleship, even) became less of a surprise if you dig around a bit in TheOtherWiki. The I-400 class of Japanese subs are the largest submarines of the WWII, and continues to be the largest subs ever built until the Soviets build their nuclear-powered behemoths in the [=1960s=]. They are capable of circumnavigating the globe ''one and a half'' times on a full tank of fuel, and actually closer in concept to a submersible ''aircraft carrier'' (granted, their planes are ambhibious). Couple that with the advanced powerplant Fog Fleet has and the fact that 401 doesn't have any planes with her, that means there is enough room and power to store and (barely) operate the WaveMotionGun.

*** Or the Fog destroyed the underwater portion of the Chunnel.

*** Keyword from the backstory is Climate Change and as we know it today the North Pole freezes less and less and raising sea levels might contribute to the Bering Straight not being the shortcut you think it might be.

** The Channel Tunnel linking Britain and France should still be running. Both terminals are either above the 20 meter waterline or could easily be protected from water. There's no reason the two nations wouldn't be connected unless the Fog deliberately destroyed the terminals (which goes against their general ban on attacking land targets) or if one or both countries cut ties deliberately (equally unlikely given the volume of trade that goes through, a naval/air blockade would make the tunnel of vital importance).

** China was discounted as a producer of harmonic torpedoes because it was devoting resources to intervention in the European conflict. Continental Europe (including Russia) is busy setting itself on fire in an unusual repeat of WorldWarOne while Britain is even worse off than Japan (somehow). It's pretty much America or nothing.

** The 20 meter rise in sea levels that feature in the backstory are notably absent from the London scenes: Chihaya Shouzou and Musashi have a conversation in London's Hyde Park, which is low enough in elevation for their park bench to be underwater at high tide; Buckingham Palace would be entirely flooded even at low tide.

* England apparently hasn't changed socially since the ''Edwardian Era'' in the manga; the country apparently still relies on the aristocracy for leadership and even fashion appears to be terribly old-fashioned.

** China was discounted as a producer of harmonic torpedoes because it didn't have the technology base required. Continental Europe (presumably including Russia) is busy setting itself on fire while Britain is even worse off than Japan (somehow). It's pretty much America or nothing.

* Why not just go to China? Seriously, it's a fraction of the distance, and it's got a land connection with India, Russia, Europe and Africa. Several decades is more than enough time to build up some pretty impressive overland trade routes.

* In the anime, Takao sacrifices her physical body to reconstruct the I-401. However, considering she still retains her core and processing power, there should be nothing that prevents her from reconstructing a physical body. It wouldn't take a lot of nanomaterial for that, and the Ars Nova should have at least that little extra to spare.

* An anime-only instance. There are only six Nagara-class cruisers ever made, and they were all sank during WWII and presumably raised up from the depths by the Fleet of Fog in the intervening years. Earlier on the series, the name ship ''Nagara'' was sunk by I-401's crew while defending the SSTO. Cue episode 8, and we see that Kongou's fleet consisted of her, Maya, and ''six'' Nagara-class cruisers. So where did that one extra Nagara-class ship blockading Iwojima came from?[[note]]While it is possible for the Fleet of Fog to raise back ships recently sunk, it takes a lot of time as Hyuuga in the manga demonstrated.[[/note]] And then you see the fleet pursuing I-401 in Episode 11, which had ''twenty two'' Nagaras.
** It's possible that most of them were active decoys like the ones I-401 uses. This, however, is not alluded to anywhere in the anime.
*** Actually, since the Fog ''don't'' use the hulks of sunken ships (as the very existence of Hyuga and Haruna prove), this is a non-issue.
**** But the way the first episode handled it seems to feel like it an issue. The cores seem to be limited to WW2 era ships and non duplicate-able in the manga but since the anime had a need for a bunch of easily disposable mooks, they decided to just copy paste the nagara class. I think.

--->'''Kyouhei:''' Oh yea, that reminds me. Why are all of you Mental Models girls? Aren't there any guys?\\

*** Actually, since the Fog ''don't'' use the hulks of sunken ships (as the very existence of Hyuga and Haruna prove), this is a non-issue.

** Also, despite Russians referring to ships with masculine names with ''male'' pronouns, the Mental Models of Soviet Navy Fog ships (assuming if any appear) are still female as shown with [[http://i.imgur.com/6SsDxb1.png the mental model of the Soviet B-67 nuclear submarine]] created by Ark Performance in a cross promotion for the 2013 film Phantom, a film about a Soviet nuclear submarine.
*** Actually, Russian SHIPS are male, subs are still referred to as female.

** Despite the US Navy's large presence in WWII, especially in the Pacific, no Fog ships based on American vessels have been seen yet. Why is this so? One possible explanation is that, since America is one of the few (if not only) countries to retain most of its military power and industrial capacity, the American branch of the Fog Fleet is concentrated more in the Eastern Pacific and Western Atlantic, keeping the US Navy at bay. [[spoiler: This is confirmed in Episode 11, as a Fog task group made up of American ships arrives to interdict Iona from reaching Hawaii.]]
** The InUniverse reason why [[SpaceshipGirl all Mental Models are girls]] according to Iona is a hilarious mix of this trope and {{Handwave}}.

*** Also, despite Russians referring to ships with masculine names with ''male'' pronouns, the Mental Models of Soviet Navy Fog ships (assuming if any appear) are still female as shown with [[http://i.imgur.com/6SsDxb1.png the mental model of the Soviet B-67 nuclear submarine]] created by Ark Performance in a cross promotion for the 2013 film Phantom, a film about a Soviet nuclear submarine.
**** Actually, Russian SHIPS are male, subs are still referred to as female.

** It's possible that most of them were active decoys like the ones I-401 uses. This, however, is not alluded to anywhere in the anime.