On 13 March 1861, the Russian corvette Posadnik (Посадник, 1856), captained by Nicolai Birilev, arrived in Tsushima island in the inlet of Ozaki, the captain demanding landing rights. This event triggered fear in the Japanese Shogunate, as the Russians had already attempted to breach Japan's isolation policy in the northern island of Hokkaido with the events involving Adam Laxman in 1792, the burning of villages there in 1806, and the events leading to the arrest of Vasilii Golovnin in 1811. At that time, only a few Japanese ports were open to foreign ships (Hakodate, Nagasaki, Yokohama), and Tsushima was clearly not one of them, thus suggesting unfriendly intentions on the part of the Russians. If taken over by the Russians, Tsushima could have become an effective base for further aggress