Hyakuemu / 100 Meters is the collaboration of two charismatic lead creators emerging in the fields of manga and animated filmmaking. Uoto and Kenji Iwaisawa are different artists, brought together by the illogical, mesmerizing, deeply human passion that fuels this story.

Manga artist Uoto loves humanity. That much is already evident in Chi / Orb: On the Movements of the Earth, the work that consolidated him as one of the most interesting emerging voices in the otakusphere. Its story about the pursuit of heliocentric studies in an environment where that’s akin to throwing your life away made something clear: his infatuation with people has no room for idealization. It’s not rational individuals seeking scientific advancements for the greater good that interest the author, nor people who oppose geocentrism for the sake of others. What Uoto can’t help but be fascinated by is folks who know they’ll be branded as heretics and likely killed for their actions, yet feel the urge to continue on this path for self-serving reasons. It’s a series about the unstoppable nature of human curiosity, which can make people knowingly sacrifice everything just because the skies would be beautiful if their rules made more harmonious sense. Humankind is crazy like that, and so Uoto is drawn to it.

While Orb’s anime adaptation was respectable enough to get across the author’s worldview, it also received criticism from some industry titans for the production’s willingness to compromise within a story about individuals who refuse to do that; our write-up about the series attempted to shed light on some understated qualities of the anime, while also giving credence to that angle of criticism. At the very end of that piece, we referred to an upcoming project that could finally marry the recklessness that Uoto is drawn to and a similarly uncompromising approach to animation. That was, of course, Kenji Iwaisawa’s theatrical adaptation of Hyakuemu.

In the same way that Uoto has quickly emerged as a mangaka to keep track of, Iwaisawa’s irruption with the release of ***On-Gaku ***in 2019 placed him in the spotlight. Despite earning immediate acclaim in this field, Iwaisawa has always been transparent about his roots lying elsewhere—as well as the fact that he had absolutely no idea how animation is supposed to work when he started, and to some degree, even now. Rotoscoping has become synonymous with his name, an inseparable part of his identity as a creator, and yet he had no idea that term even existed when he first stumbled into this method. Understanding Iwaisawa the director mandates that you first understand him as an impulsive, obstinate, reckless person who loves marching ahead once he’s had an idea. That’s how he spent the better part of a decade creating a debut film that he decided to begin after a short conversation, and in many ways, the attitude behind Hyakuemu as well.

As he has discussed in outlets like his CINEMORE conversation with director Tetsuya Mariko and his interview for the September 2025 issues of ScreenAlpha, Iwaisawa was a pupil of late cult film icon Teruo Ishii. What he makes very clear anytime he speaks of him with reverence, though, is that it wasn’t necessarily filmmaking that he learned from his mentor. Already a great veteran back then, Ishii had adopted a rather laid-back attitude and an interest in raising younger generations of artists, so he became a parental figure of sorts; not an exaggeration, given how Iwaisawa jokes about what he did (or didn’t) learn from Ishii. The already impulsive yet nonchalant student was influenced by someone with a similar mindset, in ways so fundamental that he feels like he can only appreciate them nowadays. From that attitude to the view of collaborative filmmaking as an opportunity to unearth new talent, there’s a lot of Teruo Ishii still within Iwaisawa.

Naturally—and despite not focusing on learning the specifics of filmmaking from him—he attempted to apply that experience to the same live-action field as his mentor. However, one simple thing got in the way of him ever finishing his first movie: he didn’t enjoy the process of making it. With another one of his bold swings, Iwaisawa decided to combine that desire to create movies with his childhood dream of becoming a mangaka, hopefully resulting in a process that would compel him to finish his work. Without any formal training in drawing, the solution that felt natural to him was recording real actors and then drawing over them.

Again, this is something Iwaisawa did without having any idea about the long history of rotoscoping as a technique. Rather than learning the specifics through the experiences of other artists, he went through endless trial and error to first create a short film, and then embarked on a 7-year-long adventure to bring On-Gaku to life. Even as he has become acquainted with more standard workflows since then, Iwaisawa has developed distinct views of animation production. And those are, to put it simply, amusingly alien to many of his peers. Regular tasks in traditional pipelines can appear cumbersome or restrictive to him, whereas his own ideas require a level of obstinacy that oftentimes makes them appear impossible to individuals used to regular animation projects. Signing up for an Iwaisawa work means getting a taste of something that will feel entirely unique, because he wrote his own recipe book before ever stepping into a single regular kitchen.

Given that their rise as critical darlings has overlapped, it’s no surprise that Uoto and Iwaisawa were aware of each other. In conversations between the two like the one published by AnimeAnime around the release of Hyakuemu, the former explained that he’d heard of *On-Gaku *after it became a cult hit, but hadn’t gotten around to watching the film. It wasn’t until Iwaisawa was slated to adapt a work of his that he made time for it, which made him fall in love with the director’s power of expression; an opinion shared by his parents as well, as if more approval was needed. If there’s someone who is an outright fan of the other, though, that would be Iwaisawa. *Orb *had caught his attention before he even read a single page of the series. Something about its title, theme, and even its cover design felt deeply novel to the director. Giving it a read confirmed those suspicions, starting his self-proclaimed Uoto Enthusiast Era.

That passion drew Iwaisawa to Hyakuemu, the mangaka’s professional debut about 100-meter sprint races. While rougher than Orb in his eyes, even that aspect ended up being very attractive to the director. The way you could already feel Uoto’s distinct, thoughtful authorial voice in a series he came up with when he was barely 20 years old convinced Iwaisawa that Orb hadn’t been a fluke. What he had no way of imagining is that, just a couple of weeks after he’d read it, Pony Canyon producer Yusuke Terada would reach out to him with a pitch to direct an adaptation. Delighted with such a timely opportunity, Iwaisawa accepted the proposal. That was in July 2021, a bit over 4 years before the eventual theatrical release of Hyakuemu.

While we’ve characterized the director as both a big fan of the source material and an impulsive individual, even he had some doubts about his compatibility with Uoto. That personality is precisely something that separates him from the mangaka—again, a fact that becomes clear in every one of their interactions, like this conversation for Animate Times. Uoto is wise beyond his years and very articulate about the viewpoints he expresses through manga, while Iwaisawa admits to being driven purely by passion and his own momentum. Whenever he’s asked about which character in the story he resembles the most, he’ll joke about not giving as much thought to life as any of them do, while also praising Uoto’s ability to convey such complex worldviews through simple and resonant language. Could two artists with such different demeanors manage to be on the same page, especially when this involves an anime director already known for ignoring his field’s common sense? The fact that we’re publishing this article should be a good hint that yes, they could.

What’s important to understand is that, for as different as the two creative leaders are, their interests can align at a very fundamental level. Even if he doesn’t approach it from the same anthropological and philosophical lens as Uoto, Iwaisawa is also fascinated by people’s behavior. This much is clear in his biggest influences as a filmmaker, something that has also taken years for the director himself to process. In our article about On-Gaku, we quoted Iwaisawa’s admission of love for the likes of Takeshi Kitano and Mamoru Oshii. Traces of their style can still be seen in Iwaisawa’s current work, but over time, he has realized that it’s a certain anime legend whom he’s drawn to the most. If I say that they’re a Ghibli director, you might assume that it’s Miyazaki’s impulsive genius that he feels kinship with. And that would be wrong. Instead, it’s Isao Takahata’s obsession over people’s behavior as a means of fleshing them out that resonates the most with Iwaisawa.

Again, you’d be hard-pressed to find similarities between Iwaisawa and Takahata as individuals. The former wasn’t even a long-time fan of the latter, having watched most of his work as an adult who was already heading into animation production; at most, he has found himself understanding why some works of his had clicked with him as a child, now that he has a better understanding of himself. His rotoscoping-based style is inherently close to the physical reality of people, but perhaps more important is his growing interest in turning the camera toward procedures. Like Takahata once did, perhaps better than anyone else, there’s an interest in the material day-to-day realities of people and collectives, as a way to learn about them.

Talking to Gigazine, Iwaisawa made it very clear that he doesn’t have a utilitarian view of character animation. On the contrary, the director sees the accumulation of seemingly useless movement as the building blocks for genuine humanity, as opposed to crude copies of reality. The same mindset is applied to actions themselves: without being a slow film in the least, Hyakuemu happily lingers in scenes that focus on minutiae about its sport, following Iwaisawa’s instinctive drive to humanize the cast. It may be expressed in a language totally unlike Uoto’s, but they share the same core.

Anecdotes during Hyakuemu’s pre-production confirm that this unlikely pair could see eye to eye. In an interview with Mantan, the original author recalled the reason why he started his career with a manga about 100-meter races, even though their short duration made them ill-suited for serialization. Back during the 2016 Olympics, Uoto happened to come across a race that featured a player being disqualified over a false start. The weight of mere fractions of a second had derailed 4 years of preparation, for what could very well be his last Olympics. There was a sense of horror in there, but also an awe-inspiring resilience by those who do it regardless, which he wanted to portray in his manga. While its preceding one-shot failed to get recognition during the awards he presented it to, it caused a strong enough impact within the publisher to eventually lead to* Uoto*’s first serialization.

Move forward a few years, and Iwaisawa found himself needing to restructure Hyakuemu’s story. Adapting a 5-volume manga into a movie under 2 hours demanded tightening the focus, which he decided to do around the most important characters. Out of all moments he had to cut, he has repeatedly singled out a disqualification over a false start tied to an arc they couldn’t include as the most heartbreaking. This is no coincidence; Iwaisawa’s own research into the sport also left him fascinated with the contrast between the lengthy preparation and the brief, often cruel nature of these races. Two radically different artists, at different points in time, had gravitated toward the exact same type of conflict.

Even though the script underwent 4 drafts as the director and author went back and forth with their proposals, these overlapping interests explain why Uoto was on board with essentially everything the director proposed. Instead, his suggestions focused on smaller details to sharpen those pitches, like the exact placement of certain lines. When comparing the adaptation and source material, it couldn’t be any more obvious that a mangaka known for eloquent, lengthy monologues and a director whose first idea was to remove them all to express those views viscerally use different tools. When it comes to the purpose of those tools, though, the two are in agreement: it’s all about capturing the alluring madness of humanity.

With the director and author agreeing about what to depict, the next hurdle was finding an environment to do so. On-Gaku had largely been animated by Iwaisawa himself, but that wasn’t going to fly for his first commercial project. Despite being given more leeway than the norm, the project did have an ultimate deadline in the form of the Tokyo World Athletics Championships in September 2025. Given the scale of the project and the need to wrap things up faster than his preceding chaotic production, Iwaisawa was initially due to join a regular anime studio to create Hyakuemu. And yet, that simply wasn’t viable. We’ve spoken at length about the industry-wide battle for resources and skillful staff members, something that Iwaisawa got to experience firsthand. Every capable team was booked for a long time, and even if there was some interest, there were compatibility issues between their traditional pipelines and the director’s unorthodox methods.

Because of that, he ended up turning his personal company Rock’n Roll Mountain into a fully fledged animation studio; if no place fit him, his own home would. In an interview for the October issue of Kinema Jumpo, Iwaisawa revealed that Kiyotaka Oshiyama’s approach not just as a director but as a leader of a small group of artists has become a big influence for him. Admittedly, he also noted that he accidentally betrayed Oshiyama’s advice by having expanded his company faster than he might’ve liked—leading a studio isn’t easy! When it comes to gathering staff, Iwaisawa used social media to recruit a mix of complete newcomers (around 10 of them) and people with an independent background who had already assisted him back in On-Gaku.

Given that the transition between indie and commercial animation spaces gave rise to new technical demands, a third faction was required: anime veterans. Due to the importance of his role, the sheer workload, and his ability to connect the team to other pools of talent, many will rightfully point to character designer **Keisuke Kojima **as a central figure. His career is one we’ve repeatedly covered over the last decade, both his appearances in critically beloved studios and his leadership roles in budding studios. A recurring topic in recent years has been his interest in using certain toolsets (specifically, Clip Studio Paint) to reformulate the anime production pipeline in more efficient ways.

While Kojima’s aversion to wastefulness is something that can be felt even in his storyboarding and direction stints, he slots very naturally into the most idiosyncratic, artistry-oriented projects that anime has to offer. It’s no coincidence that he keeps making appearances in projects like Sonny Boy, the Mononoke films, or Toritsukare Otoko; preexisting relationships with their directors and producers do play a role, but the reason they keep returning to Kojima is that his calculated approach is meant to enable creativity, not suffocate it. Had this not been the case, he might have clashed with an Iwaisawa who admitted that, despite the entire nature of this production differing from his past work, he approached everything with the same reckless freedom of his independent efforts. Industry veterans would sometimes recoil at his proposals, but in the end, everyone would get on board.

As a side note when it comes to the formation of the team, I believe it’s also important to shout out production assistantProduction Assistant (制作進行, Seisaku Shinkou): Effectively the lowest ranking ‘producer’ role, and yet an essential cog in the system. They check and carry around the materials, and contact the dozens upon dozens of artists required to get an episode finished. Usually handling multiple episodes of the shows they’re involved with. More **Sebastian Chablo **for his role; something he would most likely downplay himself. For the good and for the bad, we’re in an era of broadly globalized production of anime… but what is true for TV shows battling deadlines with armies of artists doesn’t necessarily apply to a project with Hyakuemu’s characteristics. For a high-quality movie created by a rather small team with indie roots, the number of overseas animators, compositing artists, and so on is by no means trivial. Their individual accomplishments are notable, and they’re born from smart appointments that demonstrate the resourcefulness of their management and lead artists. Everyone in the team we’ve spoken to had positive things to say about the team altogether and Sebastian’s efforts in particular, so I don’t think you can get a perfect grasp of this film while ignoring that.

This unusually diverse crew settled on an appropriately unique workflow. It began with Iwaisawa’s storyboarding, in a form closer to the live-action role than to its anime equivalent. With his mind already set on how the real actors’ performances would translate into animation, Iwaisawa encouraged them to perform in emphatic, somewhat exaggerated fashion that would feel more lifelike once stylized. But before that drawing process began, Iwaisawa would already be hard at work in the editing mines. While on the surface his first goal is to hold frames so that the live action footage gets closer to the final animation framerate, being able to adjust the timing of everything constantly is the director’s real obsession.

With two major Iwaisawa projects under his belt, it’s easier to appreciate how the temporality of film is something he gives a lot of thought to. Whereas On-Gaku maximized its deadpan comedy with comically lengthy cuts, Hyakuemu is tweaked so that there’s a snappy rhythm to most of it, even when lingering on minutiae. And of course, there’s the races themselves; getting the viewer in the headspace of the athletes by limiting those to barely over 10 seconds was a must for Iwaisawa, even though it would be much easier to drive up regular enthusiasm by cheating time and making them much longer. This is another aspect where he quickly saw eye to eye with Uoto, who’d always treasured the contrast between lengthy preparation and the blink-and-you-miss-it races.

Even if it were for the specifics about Hyakuemu’s themes that demand attention to rhythm and time, though, the truth is that Iwaisawa simply feels the need to edit his works at every step of the process. Earlier, we mentioned that he has developed his own feel for animation production, dissociated with the common sense of an industry he was never trained for. Because of that, he has verbalized his dislike for the (perceived) stiffness of the commercial anime pipeline, which has storyboards as a much more solid skeleton. From the first to the last day of the production, Iwaisawa feels the need to tweak every cut’s length and flow.

Once the edited footage was ready—as much as it could be before other editing passes, anyway—it was sent to Kojima for a process they called scene roughs; in short, he would draw around 1 in 10 frames over the recorded footage as a guideline, sometimes making changes to the framing if Iwaisawa decided that his live-action shooting hadn’t been ideal. It was only then that key animators would begin the rotoscoping, already with guidelines from the lead animator. In the making of stage held for the New Chitose Airport International Animation Festival, Iwaisawa and Kojima opened up about the ups and downs of that process. Sure, it put a diverse team on the same page and reduced the need for corrections, but they also worried that it might have restricted the freedom of animators in an environment where they wanted the exact opposite. Experiencing the unique results minimizes those worries, but I believe that the two will always strive to improve the balance between quality reassurance and artistic leeway.

An example of those scene roughs drawn by Kojima, from the Hyakuemu feature in the December 2025 feature of Video Salon. At the beginning, you can also see an instance of the framing altogether changing after Iwaisawa felt like it wouldn’t quite fit the mood he was going for.

At this point, you may feel like you already know all the basics of Hyakuemu’s production and how those directly connect with its themes. We have an author fascinated with mankind’s hijinks and a director who, from his own angle, shares that interest. The latter specializes in creating films by tracing over real actors, which anchors the animation into that humanity. While there are plenty other methods that could be used to give shape to these ideas, rotoscoping is demonstrably fitting. End of the story.

So of course, the very first thing you see in the movie isn’t rotoscoped. And that introduction doesn’t remain the sole exception.

As early as the making of the pilot film, Iwaisawa and company already noticed that amateur filming of athletes wasn’t feasible. Even riding on a bike, they could barely get the runners on screen for fractions of a second. And even if they could, the forms they’d show wouldn’t necessarily be meaningful; after all, their aim was to assign characters to specific professional athletes, whose running should feel coherent with their personalities and backgrounds. To address that, much of the running was based on 3D models that tried to capture those personal quirks. And, whenever the scene (or the animator’s own tendencies) called for it, they would simply draw them freehand. Uoto himself was mesmerized by how the rotoscoping-based realism captured details like the inertia after the races. However, as much as the accumulation of those movements adds to the veracity of the story, a Hyakuemu that always adhered to the rigidity of real bodies and 3D models couldn’t nail the subjective aspect of these races. And so, albeit with a deliberately uneven balance, we got both.

Beyond the need to combine different approaches to fully capture Hyakuemu’s appeal, Iwaisawa’s natural instincts are to experiment with different styles. As if to demonstrate that, the film opens with a special sequence directed by independent artist Ryoji Yamada. In a movie where most of the animation is pursuing grounded, realistic ideas, the very first shot you see is stylized to make it look like an ancient Greece amphora has come to life, quickly shifting and turning to depict the history of competitive running. Match cuts make both the artistry and the narrative jump through time until it lands in the real beginning of the story, the childhood arc. And that is, in its own way, another stylistically distinct part of Hyakuemu. In contrast to other acts, no rotoscoping whatsoever was used in its production, which relied on subcontracting to a greater degree than any other part.

Speaking to Anitrendz recently, Iwaisawa rationalized that choice—which already makes sense on a practical level, when you consider that it’d have to rely on child actors—by considering its placement in the timeline. From the point of view of the eventually adult characters, this childhood era would be the past, memories, something more detached. Those actions, then, would be depicted with less realism than more current events. It’s important to note that, in spite of that, the philosophy behind the film as a whole isn’t outright ignored. Even with the animation itself being less precise, aspects like the specificity of each kid’s running forms allow Hyakuemu to transition from this initial arc to everything that follows without feeling like two distinct movies are taped together.

In the transition between the two, Hyakuemu offers a taste of Uoto’s already trademark appreciation of humanity’s irrational, magnetic commitment to their goals. We start with Togashi, a prodigy child athlete. His overwhelming talent has started earning him national attention, but he claims that he doesn’t particularly have fun running. Rather than pure enjoyment motivating him, it’s the thrill of the simple but unquestionable victory that he’s hooked on and doesn’t want to let go of. This spells disaster as he grows up; buckling under the weight of expectations, fear of his development stalling and being overtaken by others, and eventually, a downward spiral once that happens. As an adult with a declining career, and especially after an injury scare, it would be much more logical to transition into a safer life. And yet, he’ll seek the thrill of running with no limiters once more.

The other pillar of the film is Komiya, a gloomy transfer student by the time the story begins. If Togashi’s motivation for running is delightfully messy, that’s even more the case for his rival of sorts. He started doing it precisely because it’s something painful; as a loner with an everyday life he hates, the temporary anguish of this physical effort is something that blurs the reality that suffocates him. His amateur running catches Komiya’s attention, but learning the proper fundamentals of the sport isn’t exactly a healthy liberation. After moving away—and especially, after simply discarding the fear of re-injuring himself—he begins staking his entire life on the goal of setting a record beyond logic itself.

Their stories intertwine with those of other athletes, each with their own view on running, yet all equally infatuated with it. Nigami, who became a recluse after crumbling under expectations and injury. Zaitsu, the unquestionable star of this generation… but hardly a standard role model, as he publicly advocates for a self-destructive, absolute dedication to victory. Tsuneda, a skillful athlete who won’t be able to reach the next level because he can’t remove his mental limiters like his frankly psychopathic competition. And of course, the charismatic Kaido. For his entire career, he’s been forced to live in the shadow of an overwhelmingly stronger rival. He understands the objective truth that he’s an eternal runner-up, but won’t hesitate to embrace escapism as motivation; “If my victory is unrealistic, I must escape from that reality”, he tells the protagonist.

Arguably the greatest clash of all those ideologies, as well as the best example of Iwaisawa’s approach to the film, is the final race of the high school nationals. It has been the topic of many conversations in official interviews and among fans since it was first released, and for good reason at that. Before he’d conceived any other scene, the director already had a clear vision for this moment. Having recently attended a track and field meeting, something had caught his eye: there were a lot of minute preparations that would never be shown on TV if you tuned in to watch a race. His interest in human procedures and wild aspirations made him envision a historically ambitious 3-minute 40-second uninterrupted cut—not one dedicated to the running athletes, but rather a single take of the camera roaming around the stadium beforehand.

There is, objectively speaking, no remarkable event. We lackadaisically move around athletes warming up, professionals preparing the stage, and a few spectators withstanding the heavy rain. And yet, it becomes increasingly harder to breathe as a palpable sense of tension ramps up. The viewer understands that there’s no race without all that preparation, both dreading and awaiting the release from that single cut. The explosion into 10 cruel seconds that can change entire lives feels all the weightier after witnessing all that precedes it, knowing that it’s still but a fraction of everything that those athletes went through to even earn this opportunity.

And when we talk about weight, it’s quite literal—look at the nearly 10 thousand sheets of paper that were required for this scene, between characters and background layers. Its animation process alone took exactly a year, from the beginning of August 2024 to the same dates in 2025. Even with such a lengthy process, it took quite a lot of collaboration to put it together; including Iwaisawa himself, who was one of the few people crazy enough to draw thousands of constantly shifting trees over the recorded footage. The lineart he finished alongside Koshiro Tokoro is only a fraction of the collective effort it took to put together such a herculean scene, but it was very much worth it.

If the lead-up to the high school nationals is the highlight of Hyakuemu’s mindset as an adaptation, the final race is the best example of the film purposefully abandoning that approach. For once, Iwaisawa said he was fine with betraying time just to spend a bit longer feeling what the competitors do. After being taken to the extreme, they’ve been shedding away parts of those complex views of running they had developed over the years. And at their core, the simplest truth remains: there are 100 meters, and the first one to reach the goal will be the strongest. That’s why they set themselves ablaze, for a short distance that condenses an entire life. There’s a thrill to that which transcends results, which is why Komiya and Togashi approach the goal with the biggest smiles you’ll see in the film. This time, the identity of the winner doesn’t really matter.

In the interview for Mantan we spoke about earlier in this piece, Uoto explained that he didn’t want a regular friendship between the two main characters. He finds beauty in the way that 100-meter races gather very different people who might as well be strangers… and yet, for an almost divine 10 seconds, they all face the same direction—literally and figuratively. For one highly specific moment, individuals who are normally separate seek the same goal. As we’ve seen, the original author and this film’s director are also noticeably different types of people; different fields, totally unlike personalities and demeanors. However, when it came to this adaptation, a shared objective made them face the exact same direction. And rather than just a few seconds, we got one hour and 40 minutes of exciting, affirming film. A damn good deal, I’d say!

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