Hi All, I hope this is not an easy question I was looking through Kraus catalog and noticed some coins start with Y# instead of KM#, for example Japan and some coins from Yemen. Why is that and what does it mean? I did some search but did not find any information. Thanks.
Back before the Standard Catalogs came out the standard references for world coins were Coins of the World 1700 - 1850 by Craig, Coins of the World 1860 to 1964 by R S Yeoman, and Mordern World Coins 1964 to date by R S Yeoman. These books used C#'s and Y#'s for the cataloging. When the Standard Catalog came out it originally used the C and Y#'s. As time passed each year some countries would be re-cataloged and the numbers would switch over to KM#'s. About ten or fifteen years ago they had most of the countries switched over but then they issued another, earlier century of coverage and they went back and started renumbering everything again from the beginning of the coverage. Today most everything now uses the KM# system, but there are still a few areas that are still cataloged with the old Y#'s. These will probably change over eventually. (China is really complex and you will find the coins there cataloged with Kahn numbers, Craig numbers, Yeoman numbers, Schojth numbers, Hartil numbers, and KM numbers depending on area, issuing authority and time period.)
Thanks all for the replies, extra thanks to Conder101 for the detail informative answer so that I do not have to ask again about C# ...