I bought this as a contemporary counterfeit. At first I thought it was supposed to be C#12a, but the characters do not match. I would like your opinions on it, especially hontonai's.
Sorry it took so long to get back to you Chase, but I had to do some real digging in my library! Jumping ahead to the conclusion I have drawn, you do indeed have a counterfeit, which may well be contemporary to the period 1829-69. Knowing the size and weight would allow the time period to be narrowed, as there was considerable debasement of the silver currency during the period these coins were legal tender. As you probably know, pre-Meiji 3 (1867) coins are not my primary area of interest, but I suspect that I have more relevant references than anyone else on this forum (with the possible exceptions of Doug and and gxseries). Unfortunately, my library struck out in trying to pin down your piece. The meaning of the two characters at the bottom of the obverse (on the right in your picture) is unclear, as each character has several possible readings, none of which seem to relate to any Japanese regnal era. They do not appear on any isshu gin coins pictured in Standard Catalog of World Coins, 19th Century 3rd Ed., by Krause & Mishler Japanese Numismatic Dealers Association Catalog, 2009 Ed. Part 2 of Japanese Coinage, 2d Ed. by Jacobs & Vermuele Coins of Japan 1st Ed. 1962 reprint, by Munro Coins of the World 1750-1850, 2d Ed. by Craig Modern World Coins 1850-1964, 13th Ed. by Yeoman begins its coverage of Japan with the first struck coinage of Meiji 3 (1870), and does not list any earlier coins despite the coverage statement in the name. Similarly, Weltmunzenkatalog, XX. Jahrhundert, 17th Ed. by Schon, as translated under the English name The Simon & Schuster World Coin Catalogue 20th Century, which includes some 19th Century coinage despite its name, starts Japanese coverage after the Meiji Reformation's currency/coinage modernization. In Craig's 2d Ed. there is no Japanese 12a, and the legends on your coin do not come close to matching either of the isshu gin shown as Nos. 11 and 12. Since the overall appearance doesn't match the 1829-37 Bunsei Isshu Gin (C#11, JNDA#09-49), we can rule it out as the coin being mimicked by yours. (The SCWC uses Craig numbers, not KM#s, for 19th Century Japan.) The look and feel style of your piece does approximate both the 1853-65 Kaei Isshu Gin (C#12, JNDA#09-53, ~10mm x 16mm, 1.89g) and the early Meiji Era 1868-69 Kawatsune Isshu Gin (JNDA# 09-55, ~9.5mm x 14.5mm, 1.88g). The obverse legend on both of those is "Isshu Gin", where yours is "Isshu" and two other characters, as noted above. Munro's only Isshu Gin illustration is an illegible drawing of the Kaei Isshu Gin. Jacobs & Vermule have a slightly better picture of that coin, and some dark blobs representing the later one. Sorry I couldn't tie it down any further, but, perhaps, at least the weight/dimensions will assist you in determining what coin it wanted to be. Good eye there!
Thank you hontonai. The size is 9.5mm x 14.5mm, so I guess it wanted to be a Kawatsune Isshu Gin. I don't have access to my scales, I foolishly left it 40 miles from me. The book I was using was a 4th Edition SCWC, where I got C#12a.
hontonai, that sure is an extremely long winded way to answer. There's one character that's bluntly absent in byrd's "coin", which is the character 銀 "gin", meaning silver in Japanese. I have no idea who have done it but I'm pretty sure it's done by someone who can read the letter silver and clearly omitted it. As to what it reads now, I have no idea as it seems to be some gibberish to me at the moment.
