What counts as a period
The period is the year or years of issue shown on the entry. An annual series appears in every year it was struck. A one-off issue appears only in its own year.
Year on the coin and release date
The year engraved on the coin is not always the year it was announced or went on sale. Here the year of issue on the entry decides. To see the latest announced by the mints, use the New Listings section, which is sorted by announcement date.
What it is for
It helps you complete a series year by year, compare the mintage of two different eras, or find a piece when all you remember is when it came out.
Pieces from before the 20th century
Coins from Antiquity to the 20th century will have their own section, Ancient coins, arriving in 2027.