間宮海峡
Japanese settlement on Sakhalin dates to at least the Edo period. Ōtomari was established in 1679, and cartographers of the Matsumae domain mapped the island, and named it "Kita-Ezo". Japanese cartographer and explorer Mamiya Rinzō established that Sakhalin was an island through his discovery of what is now named Mamiya Strait (Strait of Tartary) in 1809. Japan unilaterally proclaimed sovereignty over the whole island in 1845.