Jozef Chen’s rise through Brazilian Jiu-Jitsu has been remarkably fast, becoming the youngest ADCC European Trials champion at 19 and establishing himself as one of the sport’s most promising young talents.

What’s driven that progress isn’t just time on the mat, though.
It’s a training approach built around deliberate learning and testing every idea before trusting it.

Chen began training in Nanjing after living in several cities across Asia, with no prior athletic background and no particular sense that he was naturally gifted at sports.
What set Jiu-Jitsu apart for him was how it functioned as a problem to solve:

Jiu-Jitsu was the first time that I really wanted to get good at something.

That curiosity intensified during the COVID-19 pandemic, when reduced academic demands gave him more time to study instructionals, competition footage, and podcasts beyond what his local academy covered.

But Chen believes most practitioners misuse instructional content by absorbing it passively instead of testing it:

If I have something from training and I’ve experienced it and it feels like there’s something there, and that can often come from me watching an instructional, then I write it down.

I’m not going to watch an instructional and just write it down without having experienced it per se, because I find that there’s too much disconnect there for me to actually be able to use any of it.

His coach reinforced this through conceptual training games rather than relying solely on open sparring.

One example had him starting in side control while the bottom player attempted to turtle, with the top player barred from using chest-to-chest pressure.

Chen believes these restricted games surface weaknesses that stay hidden in unrestricted rolling, where grapplers often build habits that mask fundamental gaps:

I find a lot of people, they almost disguise their weakness in guard retention with guard offense…
Sometimes people have weaknesses the moment you get them outside of their guard of choice.

I find that it (the restriction) enables, it almost forces people to think a little bit more about problems in which you might not have thought of in an open round where everything is allowed and so on.

Even with that structured approach, Chen is careful not to over-plan every session:

Sometimes I find that if I’m too rigorous with my intent, sometimes I get a little bored.
I’m like, okay, I want to explore other things.

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