As far as I know, the earliest bronze is from the Middle East, and it is likely that from there it spread to other places.
From your own site:
QUOTE
Early Iron age archaeology in Vietnam dates to the early 1st mill. B.C.
Northeast Thailand provides some of the earliest evidence of work in copper and bronze. The latter is present at least as early as 2000 BC and thus represents one of the early world centers of metal alloying.
Early in the 1st millenium.. 850 B.C. as I got from the other site.
I'm not trying to put you down. If that's the arcaeological record, then that's it. I would have rather the Chinese developing their own bronze but if it's from the Middle East, then that's it.
I have to look into this, actually.. where bronze first developed.