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‘A Movie Shouldn’t Be Something The Audience Fully Understands After Just One Viewing’: Yasuhiro Aoki On The Layered World Of ‘ChaO’

By Kambole Campbell | 11/04/2025 1:41 pm |

A meet-cute like any other: a near-death experience unites young engineer Stephan and mermaid princess Ao Soni ChaO Neptunus, whose ensuing dates become pivotal to relations between people of the sea and people of the land.

The stakes sound high, but ChaO, from director Yasuhiro Aoki, doesn’t take itself too seriously. For starters, the mermaid princess ChaO appears as an actual giant fish on land, while Stephan bumbles through the film amid cartoonish sight gags.

The film’s world is spectacular — set in a futuristic Shanghai adapted to accommodate humans, fish-people, and every kind of sea creature in between. Futurama-esque tubes of water ferry people through the city, its buildings stacked high and rendered with lush background art. Aoki, a Studio 4°C mainstay who has worked as an animator on Mind Game (2004), Princess Arete (2001), and numerous other projects, spoke with Cartoon Brew at this year’s Tokyo International Film Festival about the making of his feature.

Cartoon Brew: Since there have been other love stories between man and mermaid, what, in your opinion, was the key to making your film feel unique?

Yasuhiro Aoki: [Laughs] Usually, in love stories with humans and mermaids, the mermaid is, you know, a beautiful princess, right? To differentiate our story, we wanted to do something different from that and incorporate a comedic touch. But if we pushed that too far, it wouldn’t be interesting anymore. One way we balanced it out was by creating very detailed backgrounds to bring something else to the movie.

Speaking of the design, what drew you to futuristic Shanghai as the setting?

I see Shanghai as a place that, both now and in the near future, has a lot of things coexisting. And also, well, China is huge — some parts feel completely new, but others feel old and unchanged. I thought that contrast was really interesting.

Plus, the hospitality was unbelievable. All the staff who supported us were so nice! The food was delicious, and if we finished everything, they’d ask, “Was that not enough?” It seemed like there was a culture where you shouldn’t quite finish all your food, which we didn’t know. Maybe that’s too much information, but the hospitality and service spirit we experienced — I wanted to depict that positively in the film.

In your collaboration with Hiroshi Takeguchi, how did you communicate what you found interesting about the city through the visual design? What was the main goal?

Actually, I didn’t have to tell him anything — because we went to Shanghai together! We explored the city together, and Takeguchi-san thought about the backgrounds. For me, I could only fully understand what he was aiming for after he gave me the completed work. Ultimately, the audience decides whether it’s good or not.

Speaking of the background art, one thing that stood out was the density of the city — it felt so lively. What was the key to keeping the animation clear and readable amid all that chaos?

[Laughs] Well, I personally think a movie shouldn’t be something the audience fully understands after just one viewing. Making anime takes time, so we love for audiences to watch again — even years later — and find something new. When we’re drawing the characters, if we have time, we want to create as much movement as possible. And for those watching in the future, we want to put as much information as possible in the background too!

I feel like those background details have a lot of great jokes — I keep thinking about the shot of the guy crossing the road in his underwear.

Oh, the guy just in his underwear?

Yes!

I’d also say there’s not just one main character — it feels like everyone’s a main character somehow.

What’s the key to making them stand out?

If you just put a character on screen, that’s more like manga, but we wanted it to feel more real. I always keep in mind that we shouldn’t forget the camera’s perspective when portraying them. I’ve been doing this job for more than 30 years, and I still think about that every time.

What prior experiences did you have in mind when working on ChaO?

ChaO was created with Studio 4°C, and I’d say that studio changed the animation scene in Japan. I’ve tried to learn as much as possible from them over the past 30 years. Naturally, the techniques I learned there are what I brought into this project.

Speaking of those techniques, I really like the linework on the characters — it feels very natural even in the wildest scenes. What was your guiding principle behind that style?

Since ChaO is a mermaid story — and you know there’s that old mermaid story by Hans Christian Andersen — we thought of it as both a fantasy and a fairy tale. We were trying to “deform” the illustrations in that spirit.

With the illustrations of ChaO herself, what was the key to making her movement work in her fish form?

There’s no scene of fish actually swimming, but you see ChaO walking, right? Since she has a tail instead of legs, when she takes steps, she swings her body — you can see that she’s struggling a bit, but that’s also part of her charm.

You mentioned being interested in contrast, and that made me think about how you created contrast between ChaO and the other characters — in movement, in look… other than the fact that she’s a big fish.

While making this movie, all I had in mind was contrast. When I was creating the characters, I started from the gap between the circle and the stick, then added detail afterward. I thought about making one character bigger, another smaller — really pushing that potential.

In finding the details beyond the circle and the stick, how did you collaborate with character designer Hirokazu Kojima?

I started from a circle, stick, or square — whatever worked. Honestly, I didn’t ask Kojima-san for much. I know his usual work, and just as I wanted Takeguchi-san to do, I wanted Kojima-san to experiment and take things further.

As for ChaO — in her fish form, she’s cute, and after she transforms into a more traditional mermaid, since the film is set in Shanghai, we wanted her to be cute in… let’s say, an “Asian” way. We wanted Kojima-san to bring his own sensibility, and that’s how he came up with ChaO’s look after her transformation. I’d say in everything he tries, he knows exactly what he’s doing. He can draw in many styles — good-looking boys and girls, or characters like in ChaO — but what he does, fundamentally, doesn’t change. That’s why I feel safe asking him to join a new project.

All images courtesy of: ©2025 ChaO Committee

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