China: How To Identify Originals/Reprints C8 Sino-Soviet Treaty

One of the most difficult original/reprint-sets of China to distinguish is C8, Signing of Sino-Soviet Treaty of Friendship, Alliance and Mutual Assistance.
Well, that friendship did not last very long, but the mystery surrounding this set lingers on. The differences are minute. Why Chinese postal authorities decided to make it so difficult for us, heaven knows. Some people have speculated:

''BTW for those interested in the PRC originals/reprints question, such matters were (and still are) regarded as state secrets in China. There are no official government pronouncements on the subject and in some cases no reliable criteria exist.''

It may be there are indeed no reliable criteria for this set! Reprints are said to have slightly whiter and thinner paper.The lining under the map should be clearer. I have only one used stamp that looks to be an original: heavy cancellation. But this one has that clearer lining (as opposed to all other used ones that I have that are CTO and thus reprints). Talking about reliable. Well, maybe someone has a thought about this matter. And it matters: originals are sold for 70 dollar mint/ 45-75 used, reprints just for some 12 mint/3 used. And there are a hell of a lot sets sold as originals that probably are reprints. I would be very apprehensive when buying this set...

Upper stamp: original, lower stamp: reprint. Obvious, isn't it?


The lining is clear in this original, look at the building and compare it with the reprint.


This CTO-stamp must be a reprint, the lining is more blurry.

I see the designer's drawn in Hadrian's Wall. "Huh! You call that a wall?"

The official catalogue by Posts & Telecom Press has the following description on the reprint:
The reprint has light yellowish green ink while the first print is dark green. The reprint has shape lines, especially for the map.

So your samples fit the description very well. The upper stamp (first print) is darker; the lower one (reprint) is lighter and yellowish. The upper stamp has rough edged lines on the map, while the lower stamp has clear and shape lines.

According to the Journal of Chinese Philately, III-1, june 1955,
there is also a difference in size:

Reprints are narrower: slightly under 50 mm compared to slightly above 50 mm in originals.

My originals confirm this!

3-2 has different colors. The original has deep green and the reprint has olive.