The story behind the coin
To understand this coin you have to understand what a 3 Mark meant in 1922. A decade earlier it had been a serious object: 16.7 grams of silver, a king's portrait, an imperial eagle. By 1922 the German mark was in free fall, and the republic replaced that silver with a disc of aluminium weighing two grams. You could rest it on a finger and barely feel it. That was the point — the coin had to cost less than the value it claimed, and by 1922 the value it claimed was nearly nothing.
The circulating version was designed by Joseph Wackerle (1880–1959), the Partenkirchen sculptor who had run the artistic side of the Nymphenburg porcelain works, with the reverse cut by Reinhard Kullrich (1869–1947), the Berlin mint's medallist and the son of a mint medallist. About 15.5 million were struck, essentially all at Berlin, whose coins carry the mint mark A — the small letter that tells you which of Germany's mints made a given coin. On 11 October 1924, after the currency had been stabilised, the whole issue was demonetised and pulled from circulation.
This series is not that coin. It is the pattern — a trial strike, made to test a die, a metal, or a production step before anyone commits to millions of them. The catalogued example is aluminium, 2.12 g, 27.67 mm, and it carries the mint mark F for Stuttgart, a mint that never struck this type for circulation. Its edge is plain where the issued coin's edge is reeded with 140 grooves. Auction records file it as Schaaf 302/G 2, referencing the standard catalogue of German trial strikings, and cross-reference the circulating type it tests as Jaeger 302.
Why Stuttgart made it, and how many were made, is simply not recorded. That is normal for German patterns and we will not paper over it: the record here is thin, and we would rather verify than invent.

