 During the 17th century, the feudal domains developed a system of feudal notes, giving currency to pledged notes issued by the lord of the domain, in exchange for convertibility to gold, silver or copper.Japan thus combined gold, silver, and copper standards with the circulation of paper money.Tokugawa coinage remained in use during the Sakoku period of seclusion, although it was progressively debased to try to manage government deficits.