Mamiya Rinzō
was a Japanese explorer of the late Edo period. He is best known for his exploration of Karafuto, now known as Sakhalin. He mapped areas of northeast Asia then unknown to Japanese. Biography Mamiya was born in 1775 in Tsukuba District, Hitachi Province, in what is now Tsukubamirai, Ibaraki Prefecture. Later in life he would become an undercover agent for the Tokugawa shogunate. He is best known for his exploration and mapping of Sakhalin (known to the Japanese as 樺太, Karafuto), which resulted in his discovery that Sakhalin was indeed an island and not connected to the Asian continent, although this had already been discovered by Jean-François de La Pérouse in 1787, who charted most of the Strait of Tartary. The strait would later be named after him in Japan as the Mamiya Strait. In 1785 Japanese explorers almost reached the Strait of Tartary to the west, Cape Patience to the east and Urup in the Kurils. In 1808 Mamiya sailed up the east coast and Matsuda Denjuro up the west coast. From near Cape Patience, Mamiya crossed the mountains to join Matsuda. The next year Mamiya sailed into the mouth of the Amur River and reached a Chinese trading