The History and Origins of Butt Battle

For the full effect of what I’m going for here, let the embedded video run while you read the article:

When you’ve been a private eye as long as I have, you start to expect the unexpected. Even then, sometimes a case comes across your desk which makes you sit straight up and take stock of the things you had taken for granted.

Take my most recent case with that tall glass of water, Riho Futaba. She’d first caught my eye after her appearance in Party Girls. A fine dame for sure, but when she waltzed in through my door, it wasn’t her curves which revved my motor. No, it was the scent of nostalgia. Party Girls walked and talked like an old flame of mine; a saucy dame that never left you feeling satisfied, but one which kept you coming back again and again just to get a taste of her: Dead or Alive Xtreme Beach Volleyball. It was enough to get me… intrigued, to say the least.

Despite initial impressions, I soon realized that Party Girls was a strawberry daiquiri to DOAXBV‘s glass of whiskey: they had their own, very distinctive flavours that made them stand out. However, this made their biggest point in common all the more glaring to this private eye: they both clap cheeks.

That is to say, they both feature their own take on a little thing called “butt battle”.

I’d always been under the impression that butt battle was an idea unique to Dead or Alive Xtreme: a goofy mini-game where two girls stand on a floating platform and try to push their opponent off using nothing but their generous derriere. Now, two women slapping their asses together in the pool doesn’t require a creative genius to envision, but that said, I had never heard of such a concept before playing DOAXVB. This makes some sense; just think about the practicality of actually doing a real-life butt battle. Just balancing on a floating platform is going to be difficult enough, let alone moving around and landing a hit that will knock somebody over without losing your own balance in the process. To even start to make this idea work, you’d need to get a sturdy, expensive platform that can hold the full weight of two adult women, and even then, your best-case scenario is some awkward, goofy, softcore titillation. It seemed like an open-and-shut case: surely this was just something Team Ninja cooked up to get a bit more sex appeal in their video game.

However, the first inkling of a real mystery here was that butt battle debuted in Dead or Alive Xtreme 2… which was nearly two years after Party Girls‘ take on the idea. As I played through Party Girls and stared intently at girls ramming their asses into each other, a case began to unfurl before me. Could Dead or Alive Xtreme 2‘s take on butt battle be nothing more than a cheap imitation of Party Girls? Somehow, I didn’t buy it. I was certain that there had to be somebody pulling the strings behind all of this, a mastermind who had influenced both games.

And I was going to be the one to find them.

As I let out a smoky breath and made my latest deposit in the ashtray bank, one thought thought filtered through the haze: I needed to get to the “bottom” of this mystery!

Exhibit #1: Party Girls

Party Girls left me with some clues that could point me towards our mysterious man behind the curtain. It struck me as odd that butt battle and Party Girls‘ “floating island contest” both had extremely similar mechanics. In both cases:

• The game takes place in a pool.
• Both girls are back-to-back on a small platform.
• You can win by faking-out your opponent.
• There’s a heavy emphasis on sex appeal.

Honestly, it would probably be easier for me to name the things that they do differently (which is practically zilch).

This led to my first deduction: to have this many similarities, it stands to reason that DOAX2 either a) completely ripped off Party Girls, or b) they were both referencing something that exists in the real world.

This, in turn, led me to my second deduction. Party Girls’ mini-games are framed as being part of a gameshow/idol competition, including an announcer and interstitial interviews with the contestants. This definitely seemed like it was intended to emulate something the audience would find familiar. So, if there really is a cultural touchpoint that these two dames shared in common, perhaps it was some sort of Japanese gameshow…?

Maybe, but at this point it was just a hunch. You don’t have to be a private eye to know that there are a lot of Japanese gameshows out there. Without more leads, this would be like finding a needle in a stack of needles.

Exhibit #2: Keijo!!!!!!!!

As I started looking into what few leads I had, one name kept popping up over and over again: “Keijo!!!!!!!!” When you’ve worked these streets as long as I have, you know that you’re onto something when every lowlife in town is singing the same tune.

Keijo!!!!!!!! is a manga (and anime) which revolves around a professional butt battling league. While it was exciting to discover a third suspect in this case, this had to be tempered: the series debuted seven years after Dead or Alive Xtreme 2, so it clearly wasn’t the originator of the idea. Furthermore, the series’ titular sport has been confirmed to be fictional, which really complicates this search for the origin point (ie, I can’t just Google “keijo” and expect to find anything that’s not about the show).* Keijo also plays quite differently from butt battle:

• The platform that the girls compete on is much larger, giving the girls more room to maneuver. There are also several different platform variations which can completely change how the fight is plays out.
• Also notable: competitors can hit their opponents with their boobs and their butts. While this development clearly makes Keijo!!!!!!!! the best version of the butt battle concept, the series still very much prioritizes the butts.
• Rather than just being one-on-one, there are several new match types, including four-player free-for-alls, 2v2, and 3v1.
• There’s also an emphasis on anime-style special moves, including highlights such as the “vacuum butt cannon“, “titty hypnosis“, “Cerberus” (which is literally an demonic dog possessing this girl’s ass), “1.6 kilo breast napalm“, “killing method battleship butt“, “k-cup magnum“, and “suction exploding butt“. Jesus Christ, I love this series.

While it’s possible that Keijo!!!!!!!! could have been directly inspired by Party Girls and/or DOAX2**, but I think it’s more likely that it was taking orders from the same mastermind behind our other suspects.

As I sat there pouring over all the crazy stuff in Keijo!!!!!!!!, and then pouring over it again a few more times for good measure, I decided that I wasn’t going to just write this lead off as a dead-end… I needed to check out Keijo!!!!!!!! for myself and see if she had any other surprises in store.

And so it was that I found myself in a smoky dive bar on the other side of town. She was made for the stage, her soulful tones serenading a house full of sad sacks. Keijo!!!!!!!! was every bit as easy on the eyes as her reputation would suggest, but what I found myself enraptured by was the legitimate intelligence just behind those emerald eyes. You see, Keijo!!!!!!!! is not just endless fanservice: at its core, it’s a trope-filled, over-the-top sports anime, but the sheer amount of fanservice transforms it into a calculated parody. This is the brilliance of Keijo!!!!!!!!: the fanservice actually is integral to the experience, because it makes the otherwise-standard anime action feel absurd. Most importantly, because it plays this entirely straight, the writing is good enough that you become legitimately invested in what’s going on in spite of the absurdity.

My heart thundered like the evening express. I needed to know more about this dame. I needed to peel back her layers… and she was only too eager to show me.

We went back to her place and she showed me all of her episodes. As I experienced Keijo!!!!!!! for myself, I came to see what lay at her center: a story about girls being friends and enjoying some healthy, good-natured competition between one another. The characters in Keijo!!!!!!!! all have their own, distinct goals that drive them. I really found myself growing attached to Nozomi Kaminashi and Sayaka Miyata, and wanted to see them succeed! Fanservice aside, Keijo!!!!!!!! is a legitimately empowering and positive series – everyone is focused on achieving their best, and supporting their friends to do their best too!

A clap of thunder rang through the night, and suddenly Keijo!!!!!!!! went limp in my arms, cutting this passionate union short. The manga had never been particularly successful, so when the anime failed to find a wide audience, the entire franchise was suddenly put on ice with no resolution. As I held her in my arms and felt her dying breaths, I couldn’t help but think that it was a tragic waste for such a promising young series.

She was dead, killed by a lone assassin trying to send me a message.

Somebody was trying to scare me off this case. Unfortunately for them, they did not understand my commitment to uncovering this mystery. There were just too many things lining up for me to believe that butt battle is not “a thing” somewhere out there in Japanese popular culture.

*While Keijo!!!!!!!! is not based on a real sport, there have been attempts to get a real-life league off the ground. There’s even video! Just watching the video though reinforces what I said earlier about butt battle being such an unfeasible idea. It looks extremely awkward rather than sexy and the platform has to be ridiculously massive to support and balance the two players.

**Funnily enough, there was actually a Keijo!!!!!!!! / Dead or Alive Xtreme 3 crossover event… so maybe there’s reason to believe that there’s a little direct inspiration drawn on Keijo!!!!!!!!‘s part.

Exhibit #3: Ketsu Battler

While I had been making some good progress thus far, it seemed that news of Keijo!!!!!!!!‘s death scared a lot of people, because my leads started coming up dryer than a hipflask on Sunday.

In my desperation, I looked into some dubious leads about a Switch butt-battling game called Ketsu Battler. It turned out that she was a two-player joke game where you put a joycon in your back pocket and then use motion controls move your character with your butt.

It should probably go without saying that she bore no resemblance to our other persons of interest in this case: they were all pool-based, had a heavy emphasis on sexualization, and had similar gameplay (which Ketsu Battler does not). It seemed like a real dead-end.

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And this is where the clues really started to dry up, and conspicuously so. I put my ear to the streets, but I could not uncover any more clues that could point me towards the identity of the man behind the mask. It seemed like I was the only man in this concrete jungle who was crazy enough to ask the big questions. Questions like “how did somebody come up with the idea of two girls mashing their asses together?”

With all my clues leading me to dead-ends, I had to put my feelers out to on the wrong side of town: the Dead or Alive Xtreme subreddit. However, even in a den of debauchery, no one was able to give me any kind of lead that could break this case wide open.

With nowhere else to turn, I took stock of the one solid lead that I had: that butt battle originated in a Japanese gameshow. If my hunch was correct, and all three of our suspects are drawing inspiration from a common cultural touchpoint, then it stands to reason that there would be plenty of people out there who have also heard of this.

With nowhere else to turn to, I nervously made a post on r/AskAJapanese positing my theory and asking if anyone else had any leads they could share.

My snooping around must have pissed off the right people, because within moments the roughnecks started to come at me and warn me off this line of questioning. These first replies went about how I expected: downvotes, a couple people making fun of me for asking a gooner question, and a couple people fanboying over Keijo!!!!!!!!

But then something strange happened…

You see, when I started making some noise on the mean streets, it was still very early in the morning in Japan. These initial reactions and comments were all posted by non-Japanese Redditors. As the hours ticked by, Japanese Redditors woke up, checked their feeds, saw my question…

And they took it seriously, because I was right all along. There was a mastermind behind all of our suspects, a mystery man pulling the strings, the big cheese behind butt battle! And, as the tips flooded in, I started to realize that this conspiracy was far more vast than I had ever imagined…

Exhibit #4: Super Galdelic Hour

One of the most intriguing tips I received from my contacts was the name of another person of interest in our case: a perp by the name of “Super Galdelic Hour“. This game was developed and published by Enix (of Dragon Quest fame!) and released in 2001 – a full three years before even Party Girls, making her the earliest accomplice we’ve uncovered thus far.

It didn’t take much digging to discover that this dame was extremely odd. Super Galdelic Hour‘s aesthetic is best described as “rainbow puke”: a constant, calculated assault on the eyes. The premise is equally bizarre: an alien scientist transforms four animals into suggestively-dressed (and questionably-aged) girls and then makes them compete against one another in mini-games. Super Galdelic Hour stands out thanks to its garishly Japanese aesthetics, so it’s no surprise that this game never made its way overseas. Like the other games we’ve looked at, butt battling (dubbed here as “hip sumo wrestling”) is just one of the mini-games on offer, and plays remarkably similarly to the other games we’ve looked at.

Super Galdelic Hour may have been a strange broad, but she sang the same tune as all the others. In spite of her bizarre stylings, Super Galdelic Hour shares a lot in common with Party Girls: they both have a “gameshow” format, have intros and outros, announcers, the girls are treated like idols, and there’s even similar camera angles. Of course, since Super Galdelic Hour came out first, that then begs the question of whether Party Girls was ripping this game off, but I don’t think that’s the case. All of our suspects in this case had their own, very distinct styles, so it seemed clear to me that they were drawing the bulk of their inspiration from an external source.

Exhibit #5: Sumo Wrestling & Shirizumo

As I was sifting through anonymous tips, I realized that there was another name that kept cropping up which I had missed at first. They were kind of a bigshot, even a civvy like you would have heard of them: “Sumo”. That’s right, this conspiracy went so deep that even a revered cultural institution like Sumo was getting implicated in it.

At some point, Sumo went and had a kid: a legitimized bastard called “Shirizumo” (literally “butt sumo”), wherein the combatants could only use their butts to push their opponent out of the circle. This version of sumo is so entrenched within Japanese culture that there is an annual shirizumo festival/tournament, which apparently dates back as far as the Edo period (anywhere between 1603 to 1868)! The modern-day festivals even take place on top of a platform, much like butt battle!

Shirizumo was checking off a lot of boxes, but it seemed clear to me that he wasn’t the man we were looking for. For one thing, shirizumo is a land sport, not a pool sport. It’s also considered more of a fun and humorous game, rather than anything remotely “sexy”.* His hands were dirty, and he was definitely close to the heart of this mystery, but the mastermind behind all of this was still out there. No, Shirizumo was not our culprit… but I was certain that he had directly influenced the man we were looking for.

*…well, there are always some exceptions.

Exhibit #6: Just… so many new suspects and copy-cats

With all these new clues coming in, this investigation was really starting to take shape. With all the clues pointing in one direction, I was fairly certain that I now knew who our culprit was and the timeline of events. It was just going to be a matter of finding them and bringing them to justice.

However, to really seal the deal, I decided to check in on a few other leads and found so many new accomplices who were involved in this conspiracy. It seemed like everybody in this town except me knew more about butts than they were letting on. While none of these leads really went anywhere or provided any new revelations, I think they’re worth mentioning none-the-less:

• First-off: Hololive held a sexy v-tuber butt battle stream back in July 2025. Interesting, but so recent as to be irrelevant to this case.
• Then there’s That Time I Got Reincarnated as a Slime, which has a whole sequence dedicated to sexy butt sumo. Shirizumo is also, apparently, the national past-time in the series’ world!
• There’s also Ai Tenchi Muyo!, which has an episode that revolves around butt-battling. However, this seems to be more akin to traditional shirizumo than it is to sexy pool sumo, so she’s a distant accomplice at best.
• Then there’s an anime called Nekopara, which has an episode where a couple catgirls get into a butt battle.
• Finally, I guess there’s also an Idolmaster game which has a sexy pool sumo mini-game in it, but I have no idea which one, and the effort it would take to find out would be pointless considering its irrelevance to this mystery… no, I did not spend half an hour trying to find it unsuccessfully, I said that it would be pointless to even try, didn’t I?

Exhibit #7: Idol Swimsuit Competition

Of all the breaks I got in this case, by far the most important was from the Redditor who claimed that butt battle originated in idol swimsuit competitions from the 70s and 80s. This matched my suspicions exactly, and the Japanese Wikipedia article they linked provided me with a bunch of solid clues I could pursue. If nothing else, it contained the first piece of concrete evidence that I could use to pin to our prime suspect to butt battle:

That pretty-much confirmed it: idol swimsuit competitions were the common cultural touchpoint that inspired Super Galdelic Hour, Party Girls, Dead or Alive Xtreme 2, Keijo!!!!!!!!, and many more besides. Mystery solved, we can pack this one in.

But this cat wasn’t satisfied yet. It was one thing to know that you were right. It was another to see a butt battle in the flesh (and plenty of flesh, to boot)!

I scoured through so many videos of idol shows, old and new, which confirmed my initial hypothesis: Party Girls was meant to emulate the sorts of things you’d see in one of these shows. However, try as I may, I just couldn’t locate any butt battle videos. Like, don’t get me wrong: I found some videos where the girls would do something sort of like butt battle, but there would always be something off about it (like it not being performed in a pool, the girls aren’t in swimsuits, or they’re not just using their butts).

I followed every lead I had, but I just could not find any recordings of a real-life butt battle.

And this is where I ran into a major obstacle: finding these videos is not easy. As far as I have been able to find, no one else in the English-language Dead or Alive community has ever looked into or discussed this topic. All information about the origins of butt battle are relegated to Japanese-language websites, which means I not only need to be able to know the correct Japanese words (which I absolutely do not), but I’d also need to be able to use the correct kanji (which I have no clue how to do). Not only that, but I was looking for video recordings that date back before the Internet itself… suffice to say, this case was getting so rough that I was starting to grow nostalgic for that needle in a stack of needles.

As I stood there before those iron gates, rain pouring down from on high, I breathed in the night air. This might be as close as I can get. I’m under no illusions that I will be the one who discovers footage of the first sexy pool sumo in recorded history. But, at this point, even if I wasn’t going to find a butt battle from the 70s or 80s, I still wanted to see something. This is why I got so excited when my search turned up this:

My jaw dropped… at long last, I’d found it. It was literally butt battle in real-life! I immediately tracked this film down and checked out what it had in store for me.

…it was literally just porn. Like, I’m not sure what I was expecting when I saw that cover, but I was hoping that it would be an actual competition between the girls. Instead, they just rub their asses against each other awkwardly and get into progressively more advanced states of undress over the course of two hours. It’s fetishized to such a point that it’s not even arousing… it’s just fucking dumb. How the fuck do you make your porn-parody version of butt battle significantly less-arousing than the real thing!?

Also, it doesn’t even take place in a pool! You couldn’t rent a pool for an afternoon???

By this point, I was about ready to throw the towel in. My best lead had turned out to be another dead end. Our suspect was dead-to-rights, but somehow still ever-illusive. I just had no way to crack this case open.

As I sat back in my office, penning a disappointing final note to this casefile, I went over my clues one last time to see if I could find something I missed.

And that’s when it hit me like a freight train. I cannot read or write Japanese… but I know where I can go to get Japanese words to search.

アイドル水泳大会#主な競技の種類, the kanji for “idol swimsuit competition”. 尻相撲, the kanji for “butt sumo”. Put them into Google and…

Bingo.

The elation I felt when I found this video was palpable. Look, I get that this whole quest was fucking stupid. This is easily the stupidest article I’ve ever written for IC2S, and I couldn’t be prouder of the results. I had a dumb idea, connected the dots, and then figured out how to find this weird, obscure, niche bit of human culture that I had figured out was somewhere out there.

That was far from the only real-life butt battle that I was able to find though:

I even managed to find a couple of older idol competition videos, the sorts of things that Itagaki and all the other gooners making butt battle content in the 2000s and 2010s would have been influenced by. Take, for example, this one (two butt battles occur just after the twenty-seven minute mark):

I’m pretty sure that this was even one of the big “Red vs White” idol swim competitions, which was the most popular idol show of this type. This means that we had the exact sort of footage of Idol Swim Competition that we’d been looking for this whole time: caught red-handed. The only way we could top that is if we found something from the 70s or 80s…

Look… that may or may not be from the 70s or 80s (hell, it could even be early 90s). It might not be the first butt battle ever televised… but goddammit, it’s the first butt battle in my heart.

About the Author

Barloq

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Writer, blogger, father. Blogging since 2012, writing my whole life. Was blessed by the chupacabra and the guardian shepherd.

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