Keicho koban was made based on the principle of kyome 1ryo, however, later, due to economic policies of different periods except in Shotoku Kyoho period, it became often made worse both in karat (content rate of gold) and ryome (a weighed value).
慶長小判はこの京目一両の原則に沿っていたが、後世、正徳(日本)享保期を除き、時代ごとの経済政策により品位（金含有率）・量目ともに改悪されることが多かった。