Sugimura Naoki was a high-ranking retainer to the Sô clan of Tsushima han in the 1770s. He is known for implementing a number of reforms and petitions to the shogunate which helped rescue the domain's dire financial situation at that time.
By the mid-18th century, Tsushima was facing severe financial difficulties. This was due in part to the growth of domestic Japanese production of ginseng, which had previously been a highly prized, highly priced, and major portion of Tsushima's imports from Korea. Over the course of the 1740s-1750s, the domain received loans or grants from the shogunate on a number of occasions, but these were not lasting, and in many cases, loans received from merchant houses went un-repaid.
Petitioning the shogunate for aid, Sugimura managed in 1776 to secure an agreement to an annual shogunate grant of 12,000 ryô to the domain; unlike the loans and grants of the 1740s-1750s which were paid out only a handful of times before being discontinued, this grant continued to be paid out by the shogunate every year until 1862. Sugimura was then permitted by the domain to suggest a number of other cost-saving measures, and effected the shutdown of domain offices in Hakata, Kyoto, and on the island of Iki.
In the aftermath of Tanuma Okitsugu being ousted from office in 1786 and replaced as Tairô by Matsudaira Sadanobu, Sugimura, for his association with Tanuma, also lost his privileged position as advisor or policy-maker within the domain.
- Robert Hellyer, Defining Engagement, Harvard University Press (2009), 91-92.