As a long-time researcher of Chinese Republic stamps I have been watching with interest the large assortment of overprints coming onto eBay in recent months.  The scenario seems consistent:  sellers are based in China, usually Beijing, and they have a large array of inverted overprints listed (usuall Sinkiang).  If you spend enough time researching these stamps you will know that there are a few of these that have been known for years, but to see an entire set of the Junks issue for sale with inverted Sinkiang overprints is beyond a joke!  Such material simply does not exist in the real world.

Where is all this stuff coming from?  The simplistic answer is China.  However I suspect there two distinct groups of material being offered here: printers' waste and forgeries.  In the printers waste category a number of sheets in the 'make-ready' process and these should have been destroyed, but seemingly not.  From this source comes seriously mis-aligned overprints, double or multiple overprints and overprints on both sides of the 'stamp'.  The other source is, of course, forgeries.  I have deliberately purchased a number of these in order to examine the overprints for type size and style and a number of other features.  In all instances the type style is slightly different, the size is slightly different and the alignment is often different too.  In the past full sheets of the lower value stamps were readily available in China and it seems that some entrepreneurial characters have acquired these are overprinted them.

Please be very aware of this problem and be very careful buying from Chinese-based sellers with a lot of material of this nature listed on eBay!