This paper will introduce the Japanese coins in the collection of the National Museum of Denmark. In particular, the collection made by William Bramsen (1850-1881) in Japan in the early Meiji period (1871-1880) covers all Japanese coins and is outstanding in both quality and quantity. It includes examples of all the so-called Twelve Imperial Coins from the Wadōkaichin coins (708) to the Kengentaiho coins (958). The Medieval and Early Modern periods are represented by the high-quality Musashi Sumigaki koban and the Taikō enbu-kin, which share similarities in design with Western coins, and coincide with the period when Japanese gold and silver coins shifted from weight to denomination. This paper also presents images of early modern gold and silver coins, Kan'ei tsūhō coins and prize coins to provide a brief history of Japanese currency.