Made from 1.89 grams (0.5 momme, a Japanese unit) of either 0.88 or .968 silver (depending on the type), these coins were produced in the late Edo period (specifically 1853 to 1869). There are three types of 1 Shu: ones from the Kaei era (1853-1865, 96.8% silver), ones from the Ansei era (1854-1865, 96.8% silver), and ones from the Meiji era (1868-1869, 88% silver). These varieties are distinguished by specific calligraphic variations, although how to tell them apart is beyond the scope of this article. The inscription on the front reads Isshu Gin (translating to 1 Shu Silver), whereas the back reads (from top to bottom, left to right) Jo (a stamp meaning Guaranteed), Gin-za (translating to silver mint) and Jo-ze. The last two characters (Jo-ze) are an abbreviation of the name of the mint director, Daikoku Joze. However, this was not his original name! In fact, his birth name was Yuasa Sakuheiei, but the Shogun of Japan changed it when Yuasa became mint director. Minted in Edo, these coins also have reeded edges, which are slanted on the vertical sides and vertical on the horizontal sides. Interestingly, these coins circulated at a rate of 1 Shu to 250 mon (Kanei Tsuho, the lowest denomination)! All in all, these Japanese bar coins make a fascinating addition to any coin collection.