Two weeks ago, the U.S. Mint announced a new baseball-related commemorative coin. While this is hardly the first coin inspired by baseball, this coin is particularly significant as it will be the first curved American coin. Seeing how one side depicts a baseball, this is an apt time to debut the new curved technology.

While most modern coins are low-relief, in ancient times many of the coins were much more curved. Perhaps the best historic parallel to the new baseball coin is ancient Greece’s Aeginan tortoise denomination. The curved nature of the both the ancient tortoise coin and modern baseball coin provide a similar realistic dimension to the coins’ obverse iconography. Despite the similarity in the high-relief aspect which enhances the imagery, the two coins were made much differently. The ancient Greek example uses the so-called “incuse square” technique which originated in ancient Lydia. During this process, the “square side” of the coin is indented to allow metal from the planchet to be transferred from the reverse to the obverse, thus making the coin’s “tortoise side” high-relief. While the technology behind the new baseball coin is classified, the significant progress in numismatic technology over 2000+ years is evident as now the the baseball coin’s reverse does not have to be indented which previously made one side of the coin essentially devoid of a meaningful design. To capitalize on the reverse’s newfound space, the baseball coin will depict a low-relief, but non-incuse glove.

It will be intriguing to see if curved coins regain the prominence they had several thousand years ago. While there would be some problems surrounding the return of curved coins to circulation, such as an inability to use them in current vending machines, they would offer certain advantages. The most notable advantage would be that curved coins would be harder to counterfeit, much like the new British pound coin.