Intelligence journey up the Amur: Mamiya Rinzo's observations in 1809 (2022)
In 1808, Mamiya Rinzo (1775-1844), cartographer, was dispatched by the Tokugawa shogunate to survey northern Sakhalin; he confirmed that Sakhalin was an island in 1809. In a second mission, Mamiya left Soya (northernmost point of Hokkaido) and sailed into the mouth of the Amur River; he reached the Qing Chinese trading post at Deren, and returned to Soya in November 1809. At the time, Sakhalin was receiving increasing geopolitical and imperial attentions from both Western and regional states. Mamiya himself had experienced a Russian attack when stationed in Iturup island in 1807.