China 1912...bisect

have someone informations about this stamp use bisect?

You should wait for an expert opinion, but I am dubious on its authenticity.

You seem to have an uncatalogued diagonally bisected 1912 Republic of China regular script overprint on Scott A17 coiling dragon 2 cent green London engraving unwatermarked. Both the original stamp and overprint were done by Waterlow & Sons Ltd. The cancel indicates a date of Sept 28, 1913 from "Kiaochow", English name of a concession city in Shantung province in northern China. I believe at the time of the cancel, the area should be under German administration, and so we should see the German name "Kiautschou". Perhaps its from outside the concession?

During the last years of the Empire (Oct 22-24, 1903 Foochow, Jun-Aug 1904 Chungking, and Apr 10-12, 1906 Changsha) due to a shortage of the 1 cent ocher, the 2 cent scarlets were bisected at the time of mailing as a temporary replacement. These are quite scarce and forgeries abound. Yours is overprinted by the Republic at a much later date, uncatalogued, and using a cheap original stamp. This is why I am suspicious. Naturally you should wait for an expert opinion. Hope that's of some help.