Looking for martial arts movie series circa 2000

Hi guys, I have been trynig to figure this out for years: at the end of the 90s/early 2000s I saw a then-contemporary martial art movie that spawend many sequels (at least 6).

I saw it on tv and it was most likely a tv or vhs product, of American production.
It had a Chinese protagonist that came to New York City looking for his brother that had become involved with the Tried (or something like that).

A scene I rember specifically is the main charcter somehow receiving a postal letter that only had his name and "U.S.A." written on it, and his firend was commenting on how fortuitous it was that he got it.
Thanks to anyone who can weight in.