20 Kopecks Trial strike, smooth edge

Trial strikes (пробные монеты) of Soviet coinage were produced at the Leningrad Mint under strict secrecy, with access tightly controlled by Gosbank. The smooth edge on this piece distinguishes it from the standard reeded production coin and marks it as an edge-variant trial — a category Ushakov catalogued separately, reflecting genuine differences in the approval process rather than simple minting errors. Very few examples were preserved outside state archives.