François de Callataÿ discussed clash dies in his keynote for RBW conference.
There was some discussion if this was Roman or not. Andrew McCabe assured attendees that indeed it appears on Roman Republican Coinage. As this is new to me, I thought I’d collect here to train my future eye.
“The features before the face on the obverse suggest this is an overstrike, but if one compares Münzen und Medaillen Basel XXVIII, 19 June 1964, lot 232, which has the same obverse die, the same features appear; hence, the anomaly must be from this die rather than from an undertype. The feature is incuse and seems to follow the circle of the reverse corn ear, and around the point of the truncation one can see leaves. Hence, this is a result of a die clash. A die clash between two incuse-engraved dies produces a raised feature on the damaged die and thus an incuse and reversed image on the as-struck coin. Compare also to lot (my number 63) [Andrew McCabe]”
“Clear die clash is visible on the obverse where the reverse exergual line and the letters L.SVL[LA] can be seen incuse before Roma’s head. A die clash between two incuse-engraved dies produces a raised feature on the damaged die and thus an incuse and reversed image on the as-struck coin. They are quite scarce to find so clear, and I have collected examples over the years, see CNG E-408, lots 423 and 431. Note also the scarcer reverse on a typically larger flan where the horse to the right on the coin is also to the right of the quadriga group. Crawford’s arrangement per obverse legend ignores the much bigger difference in the two reverse horse arrangements. The type with this quadriga sometimes come with faintly visible control marks scratched into the die that wear off over time, see Phillip Davis’ article “Control marks: Tiny letters, numbers or symbols on Roman Republican denarii offer collectors a brain-teasing challenge” in The Numismatist (Vol. 126, No. 8, August 2013), pp. 65-7. These numbers are above the horses or before or under the horses’ legs. Very close examination on this coin shows no confirmable trace, but they were so lightly engraved that they quickly wore off during die use, as indeed was likely the intention. From time to time I buy examples of this quadriga variety in order to examine the field for these elusive numbers. [Andrew McCabe]”
“This is an excellent example of a die clash, with the reversed and incuse letters AED C before the chin being a clear reflection of AED CVR on the reverse. Rarely do die clashes come so clear. A die clash between two incuse-engraved dies produces a raised feature on the damaged die and thus an incuse and reversed image on the as-struck coin. Compare also to lot [my number 70]. [Andrew McCabe]”
The obverse of this die shows either the results of a broken die, an overstrike, a double strike (direct or flipped), or a die clash. Die clash requires a negative incuse impression. There’s a tantalizing impression of a possible exergue line with lettering before the chin of Roma. It looks in relief, which would make it a flipover double strike, but I cannot see a match to the reverse exergue. At the time of consigning, I had not yet worked out which option is most likely. [Andrew McCabe]
Bill Dazell also recommended this article.