Sakhalin.Europeans discovered Sakhalin in the 17th century.
The first to visit the island in 1640 were the Cossacks, led by the ataman and explorer Ivan Moskvitin.
Three years later, the expedition of the Dutch navigator Martin de Vries went there.
However, Freese erroneously considered Sakhalin to be a peninsula connected to Hokkaido.
Disputes about whether it connects to the mainland or other islands continued until the middle of the 19th century.
In 1849, Admiral Gennady Nevelskoy crossed the strait between the island and the mainland on the military ship Baikal.
Sakhalin was marked on maps as an island, and the strait was later given the name of Nevelskoy.