# Shotoku Koban: Japan's Rarest Edo-Period Gold Coin
The Shotoku koban is a gold coin minted in Shotoku 4 (1714), and because it was issued for only slightly more than one year, it ranks among the rarest koban of the Edo period. Recently, a domestic research group announced their latest findings, suggesting that the actual number of surviving examples may be lower than previously estimated.
Traditionally, the number of surviving Shotoku koban has been estimated at approximately 200–300 pieces, but the recent survey confirmed only about 150 individual specimens. Of these, approximately 40 pieces are held in public institutions (museums and archives), while approximately 110 pieces have been identified in private collections and dealer inventories.
The Shotoku koban exhibits a gold fineness of approximately 84.3%, boasting the second-highest purity after the Keichō koban. The weight is approximately 17.7g. This coin is a product of the currency recoinage conducted during the "Shotoku Reforms" under the reign of the 6th shogun Tokugawa Ieyoshi and the 7th shogun Ietsugu, minted with the purpose of restoring the monetary fineness that had declined during the Genroku and Hōei periods.
The research group argues that the rarity of the Shotoku koban should be re-evaluated. In particular, they recommend that a comprehensive survey of surviving examples of all Shotoku gold coins, including the "Shotoku ichibu-ban" minted during the same period, is necessary. Regarding the Shotoku ichibu-ban, there is a possibility that even fewer examples survive than the koban.
Regarding market impact, the publication of these survey results suggests that trading prices for Shotoku koban may rise further in the future. The current market price for fine specimens is approximately 3–5 million yen, but considering the actual rarity, this price range could be considered undervalued.
According to Ichitendō's assessment, the Shotoku koban ranks as one of the coin types at the "pinnacle" of Edo gold coin collections, and its appeal as a long-term investment is extremely high. However, due to its rarity, counterfeits do exist; therefore, when purchasing, one should always verify a certificate of authenticity from a trustworthy authentication institution.
Source: https://www.jnda.or.jp/