This is a replica of the Tenpo Koban gold coin, a one-ryo oval gold coin minted from 1837 to 1858. - Material: Unknown (Possibly brass?) - Weight: Approximately 12.15g - Dimensions: Approximately 72mm x 39mm x 0.6mm - Markings: "保" (Ho) mark on the back - Measurements are amateur and taken with a commercially available measuring device, so please allow for some margin of error. This is just a replica, but it's a very popular gold coin for a good luck collection! There may be minor scratches that are difficult to see in the photos, so please refrain from purchasing if you are concerned about this. Thank you for looking.