What are DDO coins?

 The term "DDO" typically stands for "Double Die Obverse," which refers to a coin variety where the design elements on the front (obverse) of the coin appear to be doubled. This doubling effect is caused by a misalignment during the minting process, resulting in parts of the design being struck more than once.

The history of DDO in coins is intertwined with the history of coin minting itself. Throughout history, minting errors have occurred due to various factors such as die deterioration, misalignments, and other mechanical issues in the minting process. These errors can result in a variety of anomalies, including double die obverses.

One of the most famous examples of a DDO coin is the 1955 Lincoln cent, which exhibits strong doubling on the date and the word "LIBERTY." This error occurred due to a misalignment of the die during the minting process at the Philadelphia Mint. The 1955 Double Die Obverse cent is highly sought after by collectors and is considered one of the most valuable and well-known error coins in numismatics.

DDO coins have occurred across various denominations and types throughout history, with each instance having its own story and circumstances. Collectors and numismatists often study and catalog these varieties, adding to the rich tapestry of coin collecting.