Hi everyone, this is 服部 from coiai Inc. This one's a bonus episode.
I'm going to talk about how incredibly good "Chou Kaguya-hime" was, so if you haven't watched Chou Kaguya-hime, hit that back button right now.
If you're into tech, or the internet, or content in general, I really think this one is going to hit home for you.
So, there were some critical comments floating around on X, and I got curious about what kind of direction the story actually took, so I ended up watching it — and honestly, it was really good. I'm so glad I watched it, my satisfaction level was through the roof, genuinely glad I watched it.
Okay, from here on, huge spoilers. Like, a level above regular spoilers. Massive spoilers incoming. So turn this off now if you care. If you've already seen it, I'm not going to be critical of it or anything, so just sit back and listen in peace.
The Protagonist's Setup
Okay, first, let me start with the protagonist's setup.
The protagonist's name — as a creator, she goes by Iroha. Iroha is an absolute genius. It feels real, like this must be what a genuine top-of-the-top genius in the real world would actually be like.
Simply put, you can tell she got an elite education. Her father was probably a musician, I think? Not totally sure. Her mother, I'm not sure what she does, but she's probably the type who works hard at everything. A pretty hardworking parent, and since the father died early, she was raised by her mother alone — a single mother. And there it is, the single mother trope. But this single mother comes across as a pretty intense, toxic-parent type as you watch. The fact that this genius came out of a single mother who's kind of a toxic parent is genuinely wild — not clear if they even have much money — and that makes it even more impressive.
The school the protagonist attends — I'm not totally sure if it's a combined junior-and-senior-high school, private, or public — but from high school onward she's moved out of her family home and is living on her own, working part-time. There's a scene showing her living in a run-down apartment, so I get the sense she probably transferred into a school you enter starting from high school. Maybe she's explained the situation to her friends, not totally sure.
If it's not a combined school, then she's at a regular high-school-entry-type school, and yet she's got academic ability at a level where she could genuinely aim for Tokyo University. On top of working a ton of part-time hours, playing games, watching streams, and studying — she even says getting 6 hours of sleep would be nice — meaning under 6 hours is her normal. Having the level of focus, the level of concentration on studying, to aim for Todai while running on that little sleep is genuinely insane.
At one point you see the reference books she's using, and she's using Tetteki — the Tetsuryokukai English vocabulary book. So this is dead serious, no exaggeration at all.
Early in the story she's saying she's aiming for Humanities I, the humanities track at Todai, but that shifts a bit in the second half.
The Appeal of the Sci-Fi World-Building
And, ahem, I forgot to introduce myself properly — I go by Sukosuko Samurai, a lover of sci-fi world-building.
For example, in "Do Androids Dream of Electric Sheep?" there's the mood organ, that mood-adjustment organ thing, and there's also that detail where radiation is so intense that people wear a lead cup over their groin. That kind of setting — something that only exists inside that particular sci-fi world (well, the lead cup thing probably exists in real life too) — I love that kind of stuff, and of course Chou Kaguya-hime has plenty of it too.
Tsukuyomi (the VR World)
First up, there's Tsukuyomi, a world built by AI. Later on it turns out that's not quite the whole truth, but Tsukuyomi is basically what you'd call VRChat in today's world, I guess.
And what's amazing there is that there's an in-world currency called Fuju. Of course you can buy and sell things with Fuju, but there's also something called FujuPay, and there's a scene showing it being used like PayPay to pay at a convenience store in the real world. So the fact that it's usable in the real world too means it's an incredibly trustworthy currency. Isn't that wild — an in-game currency with that much real-world trust? I figure the currency system itself must be really secure, an excellent system that's hard to commit fraud against.
Sumacon (Smart Contact Lenses)
And then there's Sumacon. Something like smart contact lenses, basically an ultra-thin VR head-mounted display. This is amazing. Kind of like true wireless earbuds, except it's a contact lens, and putting it on takes you into VR. This is great. Close your eyes and you're in VR, open your eyes and you're in AR, something like that. Isn't that great? Really good. Simple and easy to understand. Close your eyes for VR, open your eyes for AR. Wonderful.
Bison (the Programming Language)
And there was a programming language called Bison. Probably a play on Python, and apparently Kaguya used it to build AIs, and even ported one into a Tamagotchi-like device. Must be a genuinely high-level language if it can implement something like that. Bison, nice.
The Yachiyo Cup and Where the Story Goes
And so, the protagonists enter something called the Yachiyo Cup. The goal set up is that if you place first, you get to perform alongside Yachiyo. Nice and easy to follow — the audience immediately understands "okay, let's just try to win this."
And the person currently in first place turns out to be running a fake female avatar — like a "bavinic" streamer, a guy streaming as a cute girl avatar. There are people like that in here too — wonderful, love it.
And there's also a scene where, mid-stream, Kaguya gets a "will you marry me" proposal, and this whole marriage-battle thing with the Emperor character, like an "please be my fiancée" battle — and I was just thinking, yeah, that's exactly Kaguya-hime, this is great. Wonderful. Amazing.
On the Criticism
And from here, I think this is probably where the people leaving critical comments stumbled — Kaguya and her friends started out as completely unknown, ordinary high schoolers. In the internet-streaming culture of this world, that means they're competing against people with 10-million-subscriber-level channels within like one or two months. If you translate that into today's YouTube, that's an absurd, meteoric rise. Within a world that otherwise feels this grounded and realistic, having exactly that one part be "the bright, strong-willed person just wins" — I get why, for the introverted otaku crowd, that would read as pure envy fuel, and maybe that's what turned into criticism. Not totally sure, though.
The Tachikawa Setting and the Interior Design Talk
Okay, and the depiction after they win gets pretty vivid and real. The protagonists live in — not Hachioji, sorry — Tachikawa, and you get that mountain atmosphere that's very Tachikawa. Tachikawa has buildings and towers, but if you go up to the rooftop you can actually see mountains. That's great, isn't it.
So they move into a high-rise condo in Tachikawa, and it's a pretty nice high-rise condo. What makes it nice? Things like a built-in refrigerator.
And the chair in the protagonist's old run-down apartment looks like an Eames shell chair. I wonder, did she buy that off Rakuten or something? Isn't Eames amazing though — still being sold even in 2030. Eames really is a timeless classic. A chair designed by Eames, part of what people call mid-century modern.
The protagonist was using that one, but after moving into the high-rise, it's replaced by something that's kind of similar to Eames but slightly different — a wooden chair. That one's way more expensive. If it were a reproduction piece it'd be totally within reach, but once you've moved into a high-rise condo, it's clearly not a reproduction anymore. That's the real thing.
So they've got nice furniture assembled, a built-in fridge, and a genuinely stylish kitchen. And this is where it feels so real, honestly. A streamer becoming massively famous and moving from a run-down apartment into a Tachikawa high-rise — there's an uncomfortably realistic quality to that. And the fact that it feels like something you could actually reach if you worked hard enough makes it a little bit enviable too. It reminded me a bit of that story where nobody cared that Hikakin bought a solid gold hand spinner, but he got hit with anti-fan comments over buying Häagen-Dazs.
The Farewell Live and Beat Saber
And there's this live performance that Yachiyo and Kaguya do together — well, together with the protagonist too. And that's when you get confirmation that the setting is 2030, in Tachikawa.
And at that farewell live, where it looks like Kaguya is about to head back to the moon, there's a scene where she's slicing through enemies, and it was such a great Beat Saber moment. Like, "oh, this is Beat Saber," and it worked so well.
The Sci-Fi Turn in the Second Half (Massive Spoilers)
And from here, the story goes full-on sci-fi. Kaguya goes back to the moon, making it look like this might be the end — and then, from there, it goes completely sci-fi. Genuinely full sci-fi, and honestly, you should just go watch the actual show for this part. I know it's ridiculous to say "go watch the real thing" after spoiling this much already, but I really do want you to watch it for yourself... okay, fine, I'll just say it. I'm saying it.
It turns out that Yachiyo is actually Kaguya, having traveled across time. As for exactly how that happened, please just go watch the actual show for that part. The how doesn't really matter here.
The Line Between AI and a Soul
And here's what made this so good — Yachiyo, as a character, was originally introduced as an AI. But it turns out she's actually Kaguya's soul, having crossed 8,000 years of time.
Isn't that amazing? It means that by 2030 in this world, the line between AI and a soul has become genuinely indistinguishable. It's at a level where you go, "yeah, that could plausibly be an AI." And honestly, even for us, living in 2026, that doesn't feel like much of a stretch at all — ever since LLMs actually appeared, machines starting to carry something like humanity has basically become the new normal for us too. So it really does feel like that kind of future is coming. And on top of that, the protagonist switches tracks here — she moves into science.
The Protagonist's Change of Course
She'd been saying she's applying to the humanities track at Todai, with Hitotsubashi as a safety school, but it seems she ends up switching to the sciences. Engineering, maybe, or Science II, not totally sure. Isn't that wild? She wasn't originally on the science track at all, and yet she just gets in.
And the fact that she's properly attending a research lab means she's made it into a lab, and afterward it looks like it's become her own lab. Seems like she's doing exactly what she wants to do. Not sure if she went all the way through grad school, but it's just non-stop, "this protagonist is brilliant," the whole way through. Like, she's too competent. Honestly, I really felt like she might be the most believable genius protagonist I've ever seen in anime or manga.
We All Wanted to Build Doraemon
And in the end, it wraps up with them building some kind of physical body, an artificial vessel, to house Kaguya's soul — who is also Yachiyo. And that's great.
Because honestly, didn't we all want to build Doraemon as kids? I really think so. Anyone who went into technology — whether writing code or whatever else — anyone who spends their time on computers, anyone living inside the internet, probably grew up reading Doraemon and all of Fujiko F. Fujio's other sci-fi work, "21-emon" and all that, and I bet they all wanted to build an AI that could actually reach into the real world. And watching this, it was like, yeah, exactly, that's exactly it — I suddenly found myself relating to this so hard.
But yeah, at the end of the day, I haven't actually built Doraemon myself either. And building something that incredible requires an absolutely insane amount of passion, right? And the fact that this insane passion comes from "for the sake of a friend who traveled across 8,000 years" — that's just so good. Too good. Absolutely the best.
Wrap-Up
To sum it all up: an AI that's grown through code eventually becomes indistinguishable from a soul. That's what I took away from this. All right, that's it.
Closing and a Bit of Self-Promotion
This one was a special episode, so it went out on a day other than Monday.
coiai Inc. does web development, XR work — we could build you a Kaguya-hime-style VR thing if you wanted — and on-premises AI, meaning we help set up AI that runs in a local environment. If you've watched Kaguya-hime, you probably remember that fish tank with the bubbling bamboo shoot thing — not bamboo shoot, wait, yeah, bamboo shoot — the bubbling bamboo-shoot fish tank. We do something kind of like that. Okay, that part's a lie. It's a lie, but yeah, we do that kind of thing.
And also core business system development — this part is genuinely real — we build core systems used in places like factories. If you've gotten a quote elsewhere that came back way too expensive, or had a project turned down somewhere else, we tend to pick those up, so quotes are always free, please reach out — and that's the promotional bit I never skip at the end.
And that's it for this one. Thank you. Bye-bye, and everyone, go subscribe to Netflix. Okay, that's not a paid promotion. Bye-bye.