Yamada Hagaki （山田羽書）is Japan’s oldest private paper currency. It was issued by the town of Yamada（山田） in Ise（伊勢国, Ise Province, the gateway town（伊勢神宮門前町） to Ise Shrine, from around 1610 to the beginning of the Meiji era. Yamada Hagaki is categorized as a private paper currency（私札), and, as the root of banknotes such as the domain paper currency（藩札）, is thought to be indispensable to Japanese monetary history.
However, further research is required to better understand the history of Yamada Hagaki. This report examines the Yamada Hagaki in the 17th and 19th centuries. Having observed the evolution of the design of Yamada Hagaki over time, I was able to propose a method for estimating the age of private paper currency based on their design and present my own idea of why such historical changes were observed.