I strongly recommend that, if you wish to learn more about the varieties of both the 'China'
overprints and the regular Hong Kong issues, that you buy a copy of Mr. Halewood and Mr. Antscherl's book
'A Study Of Hong Kong Definitives: King Edward VII and King George V'
A total of 6 shipments of the first issue on watermarked multiple CA paper were sent to the agencies. From examination of the different requisition numbers, individual stamps can be identified by the shades of ink used as it appears that the initial requisition was printed in bright colors and succeeding issues became more muted and dull. The first shipment of stamps to the Agencies did not have a requisition letter printed upon them by Somerset House and are referred to as the Nil Requisition. The five succeeding requisitions were numbered A through E respectively but, what is interesting is that for some reason some denominations of some issues were not printed with Requisition numbers or Sheet Numbers. The 1c to 10c denominations were printed on ordinary paper, whereas the 12c to $10 denominations were printed on chalky paper. In addition, the 50c denomination of the F Requisition, which was the first of the issues printed on Watermarked Multiple Script CA paper, was still printed on the regular Multiple CA paper even though it was printed and shipped at the time of the first requisition on the second issue.
A number of watermark varieties have been reported over the years. The 1 cent has been reported with a watermark appearing sideways and another has been reported with the watermark inverted.
The pair of the sideways watermark shown below are dated May 21, 1919 from Tientsin. I believe that only one sheet of this exists as, so far, all examples have been reported as used with Tientsin cancels and, indeed, I believe that this pair was originally from a block of at least 4 (probably 6) as a second block of two with what appears to be the lower part of the Tientsin cancel was offered for sale by Stanley Gibbons in 2010.
In addition, the 10c value has been reported with the watermark inverted and reversed (but only one used example is known to exist).
An unreported variety of the 2 cent green with an inverted watermark has also just been discovered. A couple of examples exist, both of which appear to have been cancelled in Shanghai
Although some printing varieties appear on both the regular and Hong Kong overprinted issues, due to their being some Requisitions where only stamps to be overprinted were printed, most varieties are unique to the CHINA overprinted issues. The most complete study of varieties of the Hong Kong issues was conducted by Halewood and Antscherl in their book and the listings below combine their classifications along with those varieties listed by Webb and others. It is unknown at this time if these varieties even appear on the 'China' overprints but it is possible that they do and so are listed for research purposes. Varieties of the stamps can be categorized by the following tables:
The following links will show you large multiples of the stamps. These images are huge and take a long time
to load but, if saved and opened in a program such as Photoshop, the close ups will clearly show
varieties.
Block of 56 of the 1c (MCCA)
Requisition A 25c SW Section Full
Nearly full sheet of the 25c (Huge file size)
Another nearly full sheet of the 25c (unknown
watermark)
The most well known error of printing on the first issues is known as the 'Broken Crown' which occurs at position SE 9-2. Previously this error was thought to only appear on the Nil requisition and had been repaired by the time of the D requisition. The two examples below not only prove the position but also show that the error still appeared at the time of Requisition A in November 1917, which was previously unknown. The error had been retouched by the time of Requisition D and was later repaired. This variety, which appeared on both Hong Kong and China Overprinted stamps, makes a fascinating tale. Although the stamps had been printed for some time, and indeed there had been two requisitions of these stamps sent to the Agencies (the Nil and the 'A' requisition), it was not until the 2nd February 1920 that Postmaster of the British Post Office at Shanghai brought the matter to the attention of the authorities. He pointed out that errors were being bought locally as 'philatelic curiousities' and asked whether the Hong Kong PMG had been made aware of the error as he assumed that this was appearing on the Hong Kong issues as well and asked whether the unissued sheets would be withdrawn or if the defective plates would be discarded or corrected for future issues. The Crown Agents forwarded this complaint on February 3rd 1920 to De La Rue.
On the 10th February, 1920, De La Rue responded that the plate in question was satisfactory and that in printing 'a sheet of paper may have sustained a particle of hard substance which damaged the overlay'