Questions on modern Chinese stamps

On Jan 15, 3:46*pm, Jan-Martin Hertzsch wrote:
On 10/01/11 13:30, Richard wrote:

The UV numbers that appear on Chinese stamps are identical for all the
stamps on the sheet. According to some Chinese websites, these numbers
serve as an anti - fraud measure.

Makes sense to me. Do you remember the addresses of the websites so
that you could let me (us?) know?

Thanks a lot!
Jan-Martin

PS: Does anybody know why sometimes Chinese stamps were cancelled in
red? Unfortunately, the ones (Great Wall issue) I have are off-paper,
thus I cannot say anything about the letters they were used on.

I have heard of a red Amoy (treaty port ) cancel
used on a Hong Kong stamp.

(sorry no scan available)
Blair