Volume 03 Manga guide Volume 05


Volume 4 cover

Volume 04 of the "Aoki Hagane no Arpeggio" manga covers the meeting and brief battle between I-401 and U-2501, the aftermath of the battle in the Yokosuka bay and the adventures of Haruna and Kirishima under the roof of the Osakabe mansion. The volume ends with the Japanese Army launching an assault on the mansion.

This volume includes chapters #18 to #24, which were published in Shōnen Gahōsha's Young King OURs magazine between February 27, 2011 and August 30, 2011.

This volume has been officially released in English on April 7, 2015.

Volume 04Edit

Guide LineEdit

Volume 4 tankōbon cover contains the final part of the "Aoki Hagane no Arpeggio" guide line:

  • 1914-1918: The World is embroiled in the First World War. The Admiralty Code begins the assessment of mankind.
  • 1919: The Treaty of Versailles is signed.
  • 1928: A team led by Nobel Laureate in Chemistry Fritz Haber tries and fails to extract gold from seawater to help pay off German's massive war reparations. "Edmund Gauss", the father of "Johannes Gauss" was in the team.
  • 1931: "Edmund Gauss" finds something strange in the data collected for the failed gold extraction plan.
  • 1943:
    • Imperial Japanese Navy sub-lieutenant "Kaoru Izumo" goes to study at the University of Berlin. He meets "Johannes Gauss", who finds his father's data.
    • "Johannes Gauss" begins researching the material found in his father's data, which seems to have been an infinitesimally small parts that can't be seen through a microscope. "Gretel Hexe Andvari", a student at university, becomes a laboratory assistant to "Johannes Gauss".
    • "Johannes Gauss" investigates the samples of seawater from coasts all over the Europe. He maps the coasts that contain the material. His friend "Kaoru Izumo" encounters the "Bismarck sisters" around this time.

Chaper 18Edit

This chapter opens up with the fight between I-401 and U-2501. The focus then switches back to Osakabe Makie and Haruna as the two of them establish a proper contact with some inputs by Kirishima, who had been reduced just to her Union core in the aftermath of the battle in Yokosuka bay.

The last pages of the chapter bring us back to the fight between I-401 and U-2501, where the later one has finished setting up a trap for the former with her fleet of Seehunds.

Chapter 19Edit

In this chapter we're shown the conclusion of the battle between I-401 and U-2501, where Gunzou was forced to surrender. However, the captain of U-2501, Zordan Stark, 'has pity' on his opponents and lets them live, because, apparently, he wants to sink I-401 when the whole world is watching them.

In the aftermath of that fight, we are also shown that Yamato knows Gunzou way too well and are hinted about some connection between them. The Second Yamato also makes her first appearance.

Chapter 20Edit

Ensign Maruri Hibiki is assigned as a permanent advisor officer to Hakugei III,which had survived the battle against Haruna and Kirishima and is being refitted with Cruising module, much to the discomfort of her captain, who seems to have developed a crush on her.

Meanwhile, Japanese special forces co-lead by assistant secretary Kamikage and Cruz Herder are looking for whatever from inboard of Haruna and Kirishima that had survived the battleships' explosion. Unfortunately, due to marines being spread too thin, they never discover Makie and Haruna before they leave for the Osakabe mansion.

I-401, having survived her defeat at the hands of U-2501, finally arrives to Iwo Jima. However, they are in for a surprise as a certain someone is waiting for them in the docks.

Chapter 21Edit

Hyuuga's Mental Model greets Iona and her crew in the docks after they disembark and Takao is finally alerted to Gunzou's arrival (in a rather comical way too). Takao and Gunzou establish a contact, however, the Tsundere heavy cruiser finds herself unable to confess to him and, instead, demands the Vibration Warhead Torpedo prototype. Results are ...interesting.

Meanwhile, as Makie and Haruna make their to the Osakabe mansion, Makie's caretaker Lawrence holds a conversation about the design children with the prime minister of the Northern region, Osakabe Makoto.

Chapter 22Edit

The chapter begins with Haruna's misadventures as the guest at the Osakabe mansion and continues onto her report to Kongou. Nagato, the flagship of the Second Oriental Fleet also butts in. Oh, and Kirishima is given a temporary body that looks like a teddy bear.

Meanwhile, at Iwo Jima, Hyuuga and Takao discuss the formation of the "Blue Fleet", while the former is busy repairing the I-401's hull.

Back at the Osakabe mansion, Makie discovers Kirishima in her disguise when she tries to pick the 'toy' up, but Haruna manages to convice the girl that nothing too suspicious is going on. And Lawrence receives a e-mail from Makoto with the photos of Haruna's and Kirishima's Mental Model's in the attachments.

Chapter 23Edit

Lawrence and Makoto hold a conversation about the contents of the e-mail and come to the conclusion that Japanese Army will attack the mansion as soon as they learn that two Mental Models are in it. Lawrence (Professor Osakabe) activates the robotic maids in hopes that they can stall the soldiers when they arrive, while Makoto orders a special operation to protect his 'sister' Makie.

We then see Kongou start using (human) politics against them as she opens up a blockade around Japan a little bit to allow Japanese Army launch an attack on Iwo Jima.

Speaking of what is going on that island, Hyuuga asks the I-401's crew a few questions and we learn a few things about Gunzou's time at the Japanese National Maritime Institute of Technology. And, the name of Kotono Amaha - the only one to top Gunzou academically - surfaces. Curious about that girl, Hyuuga and eavesdropping Takao hack into humans' records only to discover that Yamato is now wearing that face.

Chapter 24Edit

While Japanese Army massacres the robotic maids of the Osakabe mansion, Haruna holds a conversation with professor Osakabe and resolves to become Makie's friend. She asks Kirishima to see the girl out of the mansion safely while she deals with the Army. Let the soldiers be warned: Haruna is angry, and to a frightening extent...

Volume 03 Manga guide Volume 05