Review of Arpeggio of Blue Steel – Ars Nova – Episode 4: The Sunken City and the Splitting Sea

Quick Summary

In Arpeggio of Blue Steel – Ars Nova – episode 4, “Assault on Yokosuka,” Haruna and Kirishima begin their relentless attack on the port fortress of Yokosuka. As the human ships quickly fell, Haruna recorded and categorized their crews’ last words. Apparently, she’s an aficionado of human language. Kirishima, on the other hand, is a fan of battle lust, and she throws herself unabashedly into the fight. Gunzou ChihayaIona, and crew use the sunken city of old Yokosuka as cover, but what good is cover when the two fast battle ships can part the sea and yank the I-401 to the surface? Their combined might suspended the submarine in midair. What can even Iona with her human crew do against such reckless power? Will they soon experience regret, that word that Haruna recently stored — and that Kirishima ridiculed?

Note: This post may include spoilers, so be cautious.  

What’s in This Post

3 Favorite Moments

Moment 1

Gunzou used the submerged and destroyed subways of the old Yokosuka as cover. Capture from the Crunchyroll stream.

Gunzou really used the home court advantage. He could have led Haruna and Kirishima out to sea, but he wanted to use the old sunken city of Yokosuka to make finding Iona with sonar more difficult. Not only that, but the way the defensive barrier around the port had been built, it needed vents that generated underwater currents (7:56). By immersing the I-401 in those currents, they could move around without engines — in other words, silently. Between the sonar-scattering buildings and their silent movements, Haruna and Kirishima wouldn’t be able to detect them. You might say that this scene bordered on exposition, and yeah, it did. But I still liked it. Even better, it helped me as a viewer appreciate Gunzou’s tactical skills.

Moment 2

Things looked pretty dark for the I-401 and crew. You can see the combined Haruna/Kirishima off the I-401’s starboard bow. Capture from the Crunchyroll stream.

Kirishima’s logic might have been flawed — she said that it’d be too boring if her earlier torpedo barrage had sunk the I-401 (15:07) — but her conclusion was solid: The I-401 was still alive. That seemed to sting Kirishima’s Fog pride, and she wanted to prove once and for all that the two fast battleships were more powerful and capable than a mere submarine. Even a submarine with a human crew. So she began deploying her super gravity cannon, and Haruna agreed to help her. Onboard the I-401, Kyouhei Kashihara was visibly alarmed and didn’t know what to make of his readings, but Iona knew. She said, “The sea will spilt open” (15:35). And split it did! The combined tractor beam from the co-joined battleships plucked the I-401 from the seabed and dangled her in midair. Then they completed formation of the super gravity cannon and pointed it right at the apparently helpless sub (16:37). The animation was fantastic. The music was operatic. The two joined ships looked supremely menacing. In that moment, I had no idea how Gunzou was going to survive.

Moment 3

Kirishima thought this was her moment of triumph. Not so much… Capture from the Crunchyroll stream.

We knew that the I-401 had two corrosive torpedoes left. As the I-401 dangled by the tractor beam and as the super gravity cannon prepared to fire, Iona told the bridge crew that firing the super gravity cannon meant opening a hole for the beam. Plus, managing all of the equations to dock and prepare the super gravity cannon put the two fast battleships under tremendous stress, so if they fired, a shot might get through. So when the I-401 fired (17:56), I was hopeful! But Kirishima intercepted the shot. That means one corrosive torpedo remained. The two battleships prepared to fire. That’s when the last torpedo launcher hidden near the Mikasa fired the I-401’s last corrosive torpedo (18:21). With all of their attention consumed by the super gravity cannon, neither Haruna not Kirishima could stop it. The torpedo exploded deep in their shared heart. The two ships began to come apart. Did I say the animation was fantastic before? Well, it was, and it was even better now. This is the kind of scene where CGI excels. Simply amazing!


Did you see how Kirishima’s turrets worked? Apparently, the animators didn’t think it was cool enough for them to just swivel and shoot. The housing had to extend (for venting?), and even the barrels had to expand to show these vicious-looking green filaments. That’s pure style! And it looked great. 

All of the Arpeggio of Blue Steel – Ars Nova reviews and editorials I’ve read have forced me to come to a conclusion: I don’t think this show got enough credit for its character development. That’s especially true for the Mental Models we’ve seen. I’m not saying it’s Shakespearian, but I am saying it deserves more recognition. 

At the beginning of the episode, we get to see Haruna’s curiosity in action. She apparently collects recordings of human language, and her combined barrage on the port and its naval protectors gave her quite a few samples. But this episode wasn’t really about Haruna, though she played a big role. It was mostly about Kirishima.

Kirishima was really enjoying herself. A bit too much, maybe! Capture from the Crunchyroll stream.

In contrast to Haruna’s interest, Kirishima scorned human language as inefficient. As they increased the savagery of their attack against the defending destroyers, she even ridiculed the regret that some of the dying crew expressed, as relayed through Haruna. 

Arrogance wasn’t the only thing she exhibited. She was clearly into the battle — like, not just “Hey, I’m doing my job” but “I’m really, really into this!” As Gunzou and Iona evaded their attacks, Kirishima began to act as if she were becoming sexually excited.

Remember when Gunzou covered the sunken Mikasa with nano-particles to make it look like the I-401 was in front of the two attacking battleships? Both battleships were shocked when I-401 fired from astern. When the shock cleared, though, Kirishima’s emotions started to get the better of her. You could just see her control slipping — the animation here, like in the battle scenes, was subtle and effective. 

Kirishima was mildly annoyed at the I-401’s tactics, but that just seemed to get her even more riled up. Capture from the Crunchyroll stream.

As the I-401 hung from the tractor mean, Iona’s struggle to break free seemed to excite Kirishima even more. While Haruna remained collected, Kirishima became more and more demonstrative. Just before they fired the super gravity cannon, her look of exultation was triumphant. 

Right up until the point where the corrosive torpedo slammed down the cannon’s throat. 

Then, her staccato progression from astonishment to rage to utter disbelief to black despair was portrayed with animation that was nothing short of magnificent. As the ships exploded, as her body discorporated, Kirishima learned what the humans meant by regret. For me, the sign of an amazing moment is that I get completely lost in it. It might have been the scene in Made in Abyss where Regu is about to operate on Riko. It might have been the slow clap scene in the last episode of Zombieland Saga as Sakura decided whether to rise. But the reason I watch anime is to see moments like these.

Kirishima was enraged at her loss — but her rage changed quickly to despair. Capture from the Crunchyroll stream.

I should note that only Haruna’s fast thinking saved Kirishima’s union core from destruction in the final blast. It’s a good thing someone kept their wits about them!

But just look at Kirishima’s progression in this episode! She went from an arrogant, indomitable Mental Model who scorned things like regret to someone who finally and painfully learned exactly what regret mean — as her body burned away. 

If that’s not character development, then I don’t know what it!

What did you think of the battle tactics in this episode? What were your favorite moments? Let me know in the comments!

Other Posts about This Series

Other Anime Sites

This Site (Crow’s World of Anime!)

Copyright 2022 Terrance A. Crow. All rights reserved.

Please let me know what you think!

This site uses Akismet to reduce spam. Learn how your comment data is processed.