In the limited interactions that I've had with Arce, I've gathered that his knowledge base regarding judo and jiujitsu is one that very few novice or even seasoned practitioners would have or know.
Just from what I've read here and the exchanges we've had, I'd vouch for Arce's credentials. That said, I also know a gentleman that is part of the US Judo Federation (Kevin Asano), who can verify whether he is indeed a black belt or not.
My money is that he is indeed a black belt.
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