Who is Seika Izawa? Meet the world’s most dominant fighter outside the UFC

A colorful laser light show scans across 22,000-plus fans surrounding the ring in Saitama Super Arena. It’s Dec. 31, 2025 in Saitama, Japan, and the New Year’s Eve party is in full swing, just like the fisticuffs in the center of the RIZIN ring.

The year-end spectacular is an annual tradition in Japanese MMA, and after repeatedly missing one another like passing ships in the night, RIZIN superstars Seika Izawa and Rena Kubota are finally set to collide on the country’s biggest stage for its grandest prize.

The tale is a classic: seasoned veteran striker vs. the upstart unstoppable grappler. For Kubota, who’s perpetually stumbled at RIZIN’s final championship hurdle, it’s a last-ditch effort of sorts. It’s the polar opposite for her young rival. An undefeated titleholder, more dominant than the atomweight division has ever seen, Izawa’s record remains pristine after 17 triumphant appearances. She’s already submitted nine prior victims before Kubota, and dominated the other eight with her stellar groundwork.

Each fighter is focused yet calm, standing in their respective corners and striking their signature poses as their names are announced. After Izawa’s weigh-in shove the day prior, Kubota declines the glove touch. It’s time to throw hands, not play pat-a-cake.

In a flash of 55 seconds, Kubota collapses the champion with a picture-perfect leap-in left hook, nearly bringing Izawa’s historic reign down with her. Knees buckling, Izawa tumbles to her backside as the enthralled Japanese crowd erupts in a rare burst. Follow-up punches greet Izawa, underscoring the danger. She’s in trouble.

Until she isn’t.

Kubota continues to punch, allowing the ever-tactical champion to grab an arm and instantly swim for a submission. It’s a temporary fix, keeping her alive.

And that’s arguably where the fight ends. Kubota failed to put Izawa away, and the adjustments from Izawa are made immediately. A second-round guillotine choke soon cuts the head off the challenger, forcing a Kubota tap. It happened again.

Because Izawa was never supposed to lose.

Today, at age 28, Izawa stands alone as MMA’s gold standard below 115 pounds. Her dominance? Unparalleled. Her talent? At a level beyond her years. She’s not only the best women’s fighter not signed to the UFC, Izawa might be the best women’s fighter on the planet, regardless of promotion.

Her submission of Kubota gave her seven title wins to her name. With an 18-0 overall record as a professional, Izawa is only four wins away from tying legendary MMA pioneer Megumi Fujii’s hallowed women’s record of 22 straight unbeaten appearances. 

“The reason why I do this, my number one motivation and objective of pursuing this career, is to be better,” Izawa tells Uncrowned, “and to be the best. Compared to four years ago [when I first started MMA], I don’t think that mindset has changed.”

Izawa was destined for MMA greatness without even realizing it.

Martial arts have been her life practically from day one. As early as age 4, Izawa began training in judo in the south-central Japanese city of Utsunomiya, before taking up amateur wrestling in the fourth grade. By high school, she already showed her potential as a competitor, battling it out for judo and wrestling championships across the country.

Looking at Izawa, you’d never think, “That’s one of the most vicious fighters on Earth.” For starters, she’s simply not a large human being, standing 5-foot-3 and fighting at barely over the 100-pound mark. Yet while sumo wrestling is often thought of as the sport of giants, Izawa also practiced the Japanese art during her youth and even placed second in the country’s All Japan Women’s Sumo Championship as a senior in college.

MMA wasn’t even in the picture by the time Izawa graduated. She was content competing in three different sports, conquering them all simultaneously to the best of her abilities. The year 2020, however, proved to be a turning point. The COVID-19 pandemic shut down competitions across Japan. Izawa and her peers were out of luck. 

She had to stay active somehow. That meant jumping to a whole new world and taking over at record speeds. Just 14 months after her MMA debut, Izawa became the first woman to finish Ayaka Hamasaki — the consensus best atomweight on the planet at the time. In their immediate rematch, she won again. It’s been one-way traffic ever since.

Interactions with Izawa back then felt guarded, I recall, or perhaps naive. She had just established herself as the best fighter below 115 pounds when we first spoke. That was only five fights into her professional career, after she elbowed and punched her way to her first staggering upset of Hamasaki in late 2021. It was a monumental moment, yet Izawa still didn’t believe she was the best. The value of what she’d done had seemingly been lost on her, and I couldn’t believe it at the time. Her humility wasn’t necessarily surprising, but more so her perspective, and how she handled the moment as a whole.

Even today, despite her success, that hasn’t changed.

“I’ve never put too much weight on results,” she says. “That pressure really doesn’t lie on me because, again, I don’t really care about the results. I care about doing my best, and as a result, I might have this record of 18 wins with zero defeats. But when I step into the ring, I always feel like I did my best to prepare, and I don’t really care if I lose.”

In subsequent conversations in 2022, Izawa made it clear she didn’t want to compete in MMA for a long time. The plan was to get in, get out, take that spot as the unequivocal best, and walk away at age 30. That plan has since changed. Izawa and I caught up again in April to document all she has accomplished since then, and the story seemed pretty straightforward: Izawa is one of the best in the world, hidden by her size. 

Within days, that all got flipped upside down.

Izawa, today, is five months pregnant.

The most dominant champion in Japanese MMA vacated her RIZIN super atomweight title this past April to start a new chapter in her life as a mother.

The news came as a surprise to the MMA world. Plenty of women’s fighters have become mothers throughout their careers, but this was a champ at the peak of her powers.

Izawa didn’t want any pageantry, but RIZIN had its own idea. One that reached a much broader audience than a simple online post. Her career and life took place in the ring, so why not make this massive personal announcement there? It sure wasn’t anything she had ever imagined, but on April 12 at RIZIN Landmark 13, in front of a 10,000-plus crowd in Fukuoka, Japan, the champion made her decision official.

“I was just going to post it on social media. But then the RIZIN staff was like, ‘Well, why don’t you just announce it in front of everybody during the show?’ So I had no intention of making that announcement; it was more RIZIN PR’s idea. So I was quite astonished,” Izawa says.

“I don’t really get nervous before the fights. But for this announcement, I had no idea what the reaction would be like. You can’t really anticipate that. So yeah, I got a little more nervous than I would be fighting.”

Leave it to motherhood to finally create the moment that makes an unshakeable champion nervous. And just like her fighting career, it’s all been a calculated process for Izawa alongside her husband and fellow fighter, Kosuke “Coro” Terashima.

“We’ve been discussing this. We’re going to make sure it turns out to be a positive for our careers,” Coro says. “This has all been planned out. We’ve been working on this for about a year now, so we already have planned everything out so that we can make sure that she can get back into fighting in her career with the minimum amount of layoff, and we’re going to make sure that this experience makes us better professional fighters.”

Keeping her pregnancy a secret was tricky in the early months. Izawa intended to continue training as much as she could throughout the process, in whatever capacity was most manageable. That plan changed quickly. Given how hard she trains, she had to tone down her intensity, which raised suspicions in the gym among her teammates.

Now that the secret is out, Izawa — alongside Coro — feels well-equipped to embrace this life change. Speed, though, is still the No. 1 goal. Izawa doesn’t want to prolong her time off the throne while someone else keeps it warm. She regularly visits her local clinics to see what can and can’t be done regarding activity and her inevitable MMA return.

“The plan is to come back as quickly as possible after I give birth — continue to stay active and not step too far away from the life of being an athlete,” Izawa says.

This machine-like mentality is nothing new. It’s competition or nothing for Izawa, and Coro has seen that firsthand. For him, none of her success has come as a surprise.

“She had ‘it’ from the beginning. She was completely different,” Coro says. “She stood out because, a lot of the time, when you teach something to someone, it’s hard for them to digest it and put it into action. But for Seika, she was able to do it from [the start]. I would teach her something, and then she’d be able to do it. So for her, the speed of her evolving was just second to none.

“The reason why she’s evolving at such a quick rate is not only because of her skill set and intelligence, but also because she puts in the hard work. Even now, she’s still working out. She’s still evolving even though she’s pregnant. And she’s still learning. Just for an example, even the next day after a RIZIN fight, she still wakes up in the morning and starts running in the morning. The day after a RIZIN fight, she’s putting in the work. That’s definitely what’s helping. It’s not just her skills and talent, whatever. She puts in the hard work and the hours to get better. I think that’s the key to why she’s progressing so quickly.

“She hates to lose,” he adds. “She’ll do anything to avoid what she hates, which is losing. Her determination not to lose and her mental strength are something that definitely stands out. … Anything that comes with fighting and competing, she’s a perfectionist.”

For those in the Japanese MMA scene, the transition from Hamasaki to Izawa was jarring. Hamasaki, for years, appeared to be borderline unstoppable outside of her 2019 run-in with UFC veteran Seo Hee Ham — another all-time great atomweight.

Many MMA fans may not realize it, due to the atomweight division’s off-radar status in U.S. promotions, but Hamasaki became the first Japanese fighter to hold a major North American title when she won Invicta FC gold in 2015. With an elite judo base, Hamasaki was already an established force by that point, carrying a 12-1 record and a Jewels title to her name. She defended that strap twice, and went on the run that established her as a top-10 female fighter all-time, winning and defending the RIZIN title twice across a 13-fight span with seven stoppages. Overall, Hamasaki amassed a whopping 11 championship wins, only surpassed at the time by fellow legend Cris Cyborg.

Izawa, of course, was in the infancy of her career when they first collided. On paper, Hamasaki was a massive — and justified — betting favorite to win.

Yet from the moment Izawa entered MMA as a 22-year-old prospect, it was clear she had all the potential in the world. Give her an inch in any grappling exchange, and she’d take a mile. Her rapid progress was impossible to predict, even for her biggest believers.

“She’s the ultimate queen for now,” Hamasaki acknowledges. “She wins all of her title fights. Despite the fact that she’s running out of opponents, that’s one thing. Even with that said, she’s pretty much demolishing everybody that she faces. She’s untouchable as of right now. That’s how I would define her.”

One of the biggest knocks on MMA’s lighter weight classes over the years, whether for men or women, has been a perceived lack of finishing ability among the sport’s smallest athletes. The atomweight division, housing 105-pound women, should be a definition of that. Yet its best fighter has only increased her finishing rate over time.

That’s why she’s the best, believes Izawa’s wrestling coach, Billy Bigelow of Japan Top Team. Bigelow and Izawa have worked together plenty over the years, with their sessions often leaving the American wowed beyond expectations.

“She’s ferocious,” Bigelow says. “She wants to finish you. She’s willing to learn. She’s mixing up head kicks to f***ing double legs. It’s nasty. She’s doing s*** that guys aren’t able to do.

“Seika is very, very talented — and man, she’s fun to watch. She gets after it. She mixes it up with our boys all the time, so she’s not afraid to go in with anybody. The sky’s the limit for Seika. She’s super dangerous. I’ve trained with and coached a lot of strawweight [115 pounds] women in the UFC, and her skill set is top five.”

What Izawa is attempting to accomplish now would indeed be historic, especially considering the speedy timeline she so badly desires. She won’t be the first reigning MMA champion to leave and return to her organization’s title scene after becoming a mother. That distinction belongs to Angela Lee, a former ONE Championship 115-pound beltholder who attempted the same feat in 2019. It was a big story at the time. The difference, however, was that Lee remained champion throughout her pregnancy, then returned in 2022 to face an interim champ after a whopping three years between fights.

Having come out on top through it all and successfully unified the belts, there’s nothing she would have changed.

“Pregnancy changes your body in ways you can’t fully appreciate until you experience it yourself,” Lee says. “There were obvious physical changes like strength, endurance, flexibility and overall conditioning, but there were also things people don’t always talk about. Your balance feels different, your core has to be rebuilt. And even your confidence in your own body takes time to return.

“That said, I also discovered a new appreciation for what my body was capable of. Growing, delivering, and nurturing another human being gave me a different kind of confidence. It reminded me that my body wasn’t weaker; it had simply accomplished something incredible. Once I shifted my mindset from comparing myself to my pre-pregnancy self to embracing the athlete I was becoming, everything started to click.”

Lee said it herself: becoming a parent changes you. As a fighter, it also becomes an almost mandatory source of motivation. For someone with Izawa’s focus, that may turn out to be horrific news for future opponents.

“I can still be an athlete, and I can still be a mother. I feel I can juggle those two things around and still have the same results,” Izawa says.

“I just want to be the best in the world. I want to be the best version of myself possible. So I do this for myself for a very selfish purpose. That said, I think I can love my child with everything I have, with all my heart. These are two totally different things in my mind.”

“In any sport, superhumans who accomplish the unimaginable do it without thinking too much and make it look easy,” adds RIZIN founder Nobuyuki Sakakibara.

“I assure you that Izawa is indeed a superhuman who has the potential to accomplish the unimaginable and rewrite women’s MMA history.”

In the wake of Izawa’s absence, RIZIN announced a tournament to fill its championship void. The mother-to-be hasn’t exactly played nice with her lot of would-be challengers.

Eight fighters, including three of Izawa’s former foes, were selected to battle through the rest of the year to determine a new champion. The bracket officially kicked off in July.

To the competitors’ surprise, Izawa appeared at the announcement press conference.

Over the years, Izawa has become more vocally confident in her status as a champion. While never one for trash talk, per se, Izawa essentially performed a quick roast segment of her fellow atomweights. Everyone got the smoke, setting the tone that Izawa hadn’t lost her spot as one of the sport’s few clear titans. Even her latest adversary, Kubota, couldn’t escape.

“I think your chances of winning are probably the lowest,” Izawa said at the time. “But even if you become champion, don’t run [from me]. I’ll strangle you [again]. Don’t tap. Do you understand?”

The now-former champion sure isn’t short on confidence anymore; that’s a fact.

Still, Izawa is nearing the point of having done it all as one of atomweight’s greats, even despite her still relatively short run. Should she make a successful comeback, she’ll continue to force the question that already dominated the conversation before her exit: What’s next?

Competing in a lighter weight class than the UFC houses puts Izawa — and her divisional contemporaries — in a unique spot. Theoretically, she’s in a perfect spot; the easiest poster girl imaginable for the UFC to insert immediately and build a new division around.

Yet the heavier strawweight ranks may also be possible for her post-pregnancy, as Izawa previously held gold in the Deep Jewels promotion at that weight. It may not be the division at which she’s proven to be at her absolute best, but she’s fully capable.

For Bigelow, who has worked with UFC talent, it’s not a question of whether the Japanese superstar can hang. It’s more about what Izawa ultimately wants for herself.

“The transition [up a division] is difficult; she’s coming from a smaller weight, so who knows how that would shake out, but her skill set is that strong,” Bigelow says.

“Can she make the move to the UFC and put in the effort to go to strawweight, or do we wait it out and see if they go atomweight in the UFC? Or does she stay in Japan? She’s got a great career in Japan, so fighting in RIZIN is excellent living, and she can still create her legacy. Whatever she wants to do.”

Seeing a successful RIZIN champion cross over into UFC would be nothing new. Two of the Japanese promotion’s biggest recent stars, Kai Asakura and Kyoji Horiguchi, both jumped ship to UFC while holding titles. The same can be said for light heavyweight Jiri Prochazka, who claimed the UFC title in only his third Octagon appearance.

Sakakibara is game when it comes to growing and expanding global MMA’s reach. That’s been the reason he’s permitted his RIZIN superstars to cross over to other promotions as often as they have in recent years. But Izawa is a big piece of his roster.

Would her budding stardom be elevated and built upon by leaving RIZIN?

“Defining a ‘star’ is quite difficult,” Sakakibara says. “When you look at the level of competition and skill sets, yes, Izawa may be one of the best fighters RIZIN has seen since our launch in 2015. However, when you look at her [charisma], she’s still not quite there with our other top stars. This doesn’t mean that she doesn’t have what it takes; it’s more about the fact that she doesn’t have any quality rivals that can elevate her existence in our current super atomweight division. This issue is not solely RIZIN’s problem, but I think it’s a universal problem in the current women’s divisions where the lack of talent is undeniable. 

“With that said, I think the biggest asset that divides a fighter from being a star or not is whether people can emotionally invest in your fights or not. So even if you have the greatest skill sets and may be the best fighter, there are certain things those skill sets cannot create.”

As soon as Izawa became a champion in 2022, the UFC question became inescapable. It was not necessarily one of Izawa’s choosing, but it had to be asked. This was a budding phenom of the highest order, someone who was making good on every bit of promise she showed from the moment she first entered MMA. For many fighters in the Japanese MMA scene, there remains something extra enticing about international competition.

But for Izawa, she’s thriving. 

“I feel really comfortable here. I really love this organization,” she says. “Right now, my current goal is that I want to make RIZIN recognized internationally, and I want to make RIZIN the best organization in the world. That’s my current motivation. That said, I would still like to face international competition. I would like to challenge the top fighters. 

“I understand that the UFC’s lowest weight class is strawweight, and if there are smaller strawweights, it would be great to have them come to RIZIN’s super atomweight division.”

In the meantime, after getting into the sport so young, the fighter who was once solely focused on simply competing and being their best self has evolved into a fully-fledged role model. And Izawa is wholly embracing the shoes she hopes to fill.

“I’ve kind of learned that you have to listen to others,” she says. “It’s not all about yourself anymore. It’s not about me chasing my dreams. I have to listen to everybody else. I have to look out for everybody around me. That kind of mindset kicks in once you become a champion.

“You have a broader vision of what your responsibilities are. So right now, I’m not really thinking about myself, which kind of leads to the project I’ve been doing. I’ve been focusing more on identifying upcoming athletes and contributing and giving back to the women’s MMA industry. That’s something I have been focusing on a lot lately. So in those terms, I’ve definitely matured, and this sport has definitely grown me and matured me a lot as a human being.”

So, when all is said and done, what is the end game now for Izawa? How could someone of such intense mental determination to be the greatest possibly accept the end?

The answer is clear.

“When I realize I can’t get any better,” Izawa says.