Brockages and Clashed Dies


(Left) Brockage of Republican denarius (Plautia 12) ---------- (Right) Brockage denarius of Septimius Severus, Emesa Mint
Reverse is incuse of obverse.

Brockages result when a coin sticks in a die following striking. If the mint workers do not notice and remove it the next coin receives the impression of the coin rather than the die. The resulting impression is identical to the other side of the coin but reversed and incuse. Ubtil the late 3rd century AD. brockages showing the reverse are much less common since mint workers would be more likely to see the stuck coin in the anvil die. This turns around in the late Roman period when changes in mint practices make it more common to see reverse brockages.

(Left) Clashed dies denarius of Clodius Albinus as Augustus from Lugdunum --- (Right) Clashed dies denarius of Septimius Severus from Rome

Note inverted incuse of obverse legend and portrait.
Incuse letters yellow; normal reverse raised letters red.

If the workers were to notice the error, they could replace the coin in the anvil die and strike it again to restore the normal reverse. Since the flan had cooled this restriking might not be completely successful in erasing the incuse design and the final coin would be a combination of raised and incuse design. This would be a 'restruck brockage'. I DO NOT BELIEVE IN RESTRUCK BROCKAGES. It is a theory that has become quite widely held but no one has succeeded in convincing me that any particular coin is a restruck brockage rather than an example of clashed dies. While similar in appearance in some ways, the error that produced clashed die coins was quite different from that causing brockages. Clashed dies result when the dies are hammered together without a coin blank in place. The softer reverse die received a partial impression of the obverse. The result looks exactly like what we described as a restruck brockage. This student considers all such coins to be results of clashed dies. The extra work to restrike a brockage seems a lot to ask in a busy factory situation while accidental damage when a blank slipped out of place would seem quite common. The clashed die of Clodius Albinus (as Augustus from the Lugdunum mint) shown here also has a large raised metal 'blob' at 1 o'clock on the reverse. This area of the die was damaged severely with a piece broken away. It seems likely that the damage to this die was part of the same clashing that produced the incuse portions of the design but other coins from the die would be needed to prove the matter. I would appreciate hearing if anyone has seen another coin from this die (GEN LV - G COSII reverse) either pre or post damage. The die is made distinctive by the separation of the LV - G legend. The raised G was placed on the right side where it was erased by the incuse D of the clash.

Certain evidence of clashed dies is finding a die duplicate of the coin with both showing the same placement of the incuse design. The two Julia Domna denarii shown here are identical in die and damage placement so this, at least, is certainly clashed dies. Differences in these coins can be attributed to die wear, striking diferences and coin wear. Note the faint outline of the bust (upside down in this case) and the strong 'DO' incuse at the lower left of the reverse. Frequently on brockages such as the Septimius Severus at the top of this page, the incuse design spread a bit and is larger than the normal design of the coin that made the impression. The incuse design resulting from clashed dies, however, remains the same size since it was made by a hardened die rather than a soft coin.

Two more denarii of the same type demonstrate another interesting point. The upper coin of our pair was struck before the dies were clashed. The lower coin shows this same die pair after damage by clashing. In this case the dies were oriented in the upright position so the incuse is not upside down. While not nearly as clear as the previous pair, the folds of the drapery of the bust show near Venus' knees and incuse legend traces show on both right and left. Our bottom coin could, in theory, be a 'restruck' brockage since the damage is not present on both coins. I am, however, quite certain that finding another identical specimen will prove this also to be a clash. On the other hand, finding another coin of these dies that shows the incuse in a different position would suggest that I am wrong to deny the existence of restruck brockages. If you find this coin or know a good way to tell restruck brockages from clashed dies, please contact me.

Special thanks go to my internet friend who provided me with the last shown coin on this page. His realizing that this coin would be 'special' to me has added greatly to my enjoyment of this hobby. This is what makes the internet such a benefit to those of us interested in something as unusual as ancient coins. Online, we can meet people of similar interest who live thousands of miles away and share our common interest in numismatics.

UPDATE March 2000:

When I wrote the above paragraph about the importance of 'internet friends', I had no idea I was being prophetic. Another person located thousands of miles from me found another coin that is even more important in the quest for understanding the matter of clashed dies. This common coin of Constantine the Great was struck twice leaving a secondary image of the back of Constantine's head on the obverse. On the reverse we see two incuse artifacts of a die clash offset from each other by the same amount as the doubling on the obverse. These indicate that the reverse die was damaged by a (single) clash which was transfered to the coin twice with the double striking. Red arrows point out the obverse back of head and the incuse chin on the reverse. The striking of this coin was extremely heavy resulting in the broad spread flan that curled around the edge of the reverse die (upper left). This striking certainly would have erased the incuse of a brockage but, instead, the second strike duplicated the incuse proving the damage was part of the reverse die.

The question has been asked why the damage resulting from a die clash is always on the reverse and why the obverse was not similarly damaged. My first thought is that the reverse die was made of softer material incapable of marking the harder obverse. Whether this means the reverse was bronze and the obverse iron or whether the reverse was less fully hardened by heat is not clear. Furhter there is the question whether this difference was intentional or simply sign of the technological limit to the hardening process at the then current state of the art. I would love to see a coin showing obverse incuse from a clash. If it exists, it would open another new set of questions requiring even more study. The more we learn, the more we find we do not know.

Thanks again to the four numismatists from three countries that contributed coins to this study. Without the internet and the communications between persons of like interests that it facilitates, the bits of information provided by these coins never could have come together.

2012 Update:

I was Wrong!!!

Again thanks to an Internet friend who traded me this coin, I now must admit that there is such a thing as a restruck brockage. This AE2 of Magnentius at first glance appears to be a flip over double strike. The obverse shows a clear portrait bust and a good portion of the reverse design so the coin received two strikes from the dies and flipped over between strikes. Flipover double strikes are not uncommon. What makes this coin special is that the first strike was a reverse brockage. After one strike the coin had two reverses - one normal and one incuse. It then flipped over (intentionally by a mint worker or accidentally???) and was struck again producing a normal obverse on what had been a normal reverse and a normal reverse on what was the incuse reverse. The enlarged image at the left shows some details of the VOT / V / MVLT / X side by side with the normal on the left and the reversed incuse on the right. The coin is a bit of a mess but the longer you look at it the more details from both strikes become apparent. I said that I did not believe in the existence of a restruck brockage but this coin does appear to be one. I was wrong!


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1997, 2000, 2012 Doug Smith