Here's an 'authenticity unknown' or an example of a major variety of the series. Compare to the Daniel Ching piece (Y512.1). Note: there are many minor varieties that do not carry a premium value and most have not been documented. Minting conditions were crude in those difficult circumstances.
Stars flanking date (obverse) appear SMALL in size in comparison to other varieties; significance of the rotational alignment differences are unclear to me at this point; this example has one star upward (r) and the other (l) down. It is also worth noting that the legends are somewhat free floating in the various varieties. This example is ~35.5 mm which makes it well over the KM norm of ~32.5mm. I bought another example that looks very similar and of the same large size - it was sold as a FAKE. See comment below.
Here are a number of RARE articles on Communist Chinese Soviet coins & notes from the Moneta Library:
VIEW & DOWNLOAD:
Soviet Chinese Copper Coins ("Little Brown Book") - Hua Guangpu
Soviet Chinese Coppers - Hua Guangpu
Soviet Coins Intriguing - Hogan
Chinese Soviet Coins Intriguing - Hogan
Chinese Soviet Coins and Notes - Raeburn (1937!)
Chinese Soviet Coins and Notes - Raeburn
Chinese Communist Armies Silver Coins - Kann
Chinese Communist Armies - Kann
The premier articles on Early Chinese Soviet issues are the invaluable documents below. It covers the history, coins and notes from 1927-1935 and includes photos and a map: (with color photos; in 3 parts);
The Money of Communist China - Sandrock (3 part series)
Part I: The Money of Communist China 1927-1949 - Part I
Part II: The Money of Communist China 1927-1949 - Part II
Part III: The Money of Communist China 1927-1949 - Part III
The Comprehensive Catalog of Chinese Copper Coins ("SOVIET" extract; color illus.) - Duan
Chinese Soviet Copper Coins - Duan
Concerning my attempt to present examples conforming to the 3 types shown in KM I must emphasize the fact that among the 13 examples I have not more than two could be considered 'exactly alike. This particular coin is an oddity in more ways than one and is different enough to warrant another Y512 sub -classification number. See my other Y512 for a less ambiguous conformation to KM. Also note that, in hand, this coin is not nearly so mottled and ugly as the scan would indicate. Obverse details are a bit 'flattened' as the photo shows.
I'm now listing this one as a FAKE or contemporary counterfeit.