Mountain Climbs, River Swims, And Raw Discipline: How Hiroyuki Tetsuka Built Himself Into ‘Japanese Beast’
For most fighters, training camp means bright gyms, carefully measured drills, and tightly controlled routines. For Hiroyuki Tetsuka, it means building strength in the middle of nature.
The 36-year-old Japanese fighter has carved out one of the most unique paths in MMA, blending traditional toughness with a deeply personal training philosophy that helped shape the man now known as “Japanese Beast.”
That identity will face perhaps its toughest challenge yet at The Inner Circle on Friday, May 15, when Tetsuka meets ONE Lightweight Submission Grappling World Champion Kade Ruotolo in a lightweight MMA showdown at Bangkok’s Lumpinee Stadium. The star-studded card airs live exclusively for subscribers at live.onefc.com.
That reputation did not come from flashy theatrics or manufactured bravado. Instead, Tetsuka built the nickname through years of rugged preparation and an unusually raw approach to training that mirrors the environment around him.
He said:
“Well – whether I’m actually the ‘Japanese Beast’ I’m not totally sure, but I’m in a fairly rural environment, so I train outdoors in nature a lot. Mountain climbing, swimming in rivers – it feels like playing, but it naturally becomes training.
The approach may sound unconventional, but it has produced real results.
Now carrying a 15-6 slate with a terrifying 87 percent finishing rate, Tetsuka built his reputation through years of hard-fought battles inside ONE.
After spending much of his career competing at welterweight, he moved down to lightweight last year and immediately made a statement by stopping legendary former ONE Lightweight MMA World Champion Shinya “Tobikan Judan” Aoki in the second round at ONE 173.
Now, with another massive challenge awaiting against Ruotolo, Tetsuka continues to rely on the same lifestyle and mindset that shaped him long before the bright lights inside the world’s largest martial arts organization.
“Japanese Beast” said:
“I don’t consciously think of it as training, but I figure it naturally builds physical strength in some way. Living in nature – eating the rice – there’s a sustainability to it.
“In terms of training, rather than something spiritual, it’s more that I use YouTube to learn new techniques, and then my team and I creatively build things together. That process is fun, and the strength just came naturally from it.”
Tetsuka Builds His Own System
Unlike many fighters who follow rigid schedules created entirely by coaches, Tetsuka takes a far more personal approach to preparation.
The Japanese warrior structures much of his own training around mood, recovery, and the demands of each week rather than rigid repetition.
While he still works closely with coaches and specialists, self-analysis has become one of the foundations of his development.
That flexibility has become increasingly important as he prepares for world-class competition inside ONE.
He said:
“It varies day to day. Generally, grappling practice around midday, eat, then striking at night. Roughly two sessions a day. Wake up, do strength training, then boxing or whatever in the evening. It shifts depending on the day of the week, but two sessions a day is the baseline.
“The basics – bench press, push-ups, pull-ups, deadlifts, squats. Really fundamental stuff. I design most of it myself. That said, once a week I have a personal trainer who looks at my movement and body mechanics.”
That attention to detail extends beyond simple strength work.
Tetsuka recently traveled to Phuket, Thailand, multiple times during camp, surrounding himself with elite grapplers and fighters familiar with Ruotolo’s game. The experience gave him a clearer understanding of the challenge ahead while reinforcing the importance of adaptability.
At the center of everything remains a training philosophy built on experimentation, creativity, and understanding his own body rather than blindly following routines.
Tetsuka even joked about having an “earthworm routine,” though he admitted the real secret lies less in gimmicks and more in constant self-adjustment.
Tetsuka said:
“[I have] no secret routine. If there’s anything that might count as a unique routine, well, there’s the earthworm routine.
“Being trained in something you didn’t choose for yourself doesn’t really take root. I do have a general weekly structure, but I adjust it based on how my body is feeling day to day. I combine things flexibly and design it myself as I go.”
The Beast That Keeps Evolving
Even after years competing at the highest levels of MMA, Tetsuka continues searching for ways to improve.
The Japanese star recently opened his own gym, TGFC, a project that reflects both his growth as a martial artist and his desire to build something lasting beyond his own career.
The gym currently remains in its pre-open phase, but Tetsuka already sees it as an extension of the team that helped shape him into the fighter he is today.
That sense of loyalty has become one of his biggest motivations heading into The Inner Circle on May 15.
Tetsuka said:
“The coaches there have taken great care of me and made me stronger. I feel a real sense of obligation to them. I want to win for them.”
