The Russian corvette Posadnik arrives at Tsushima…
March 1861 CE
This event sparks 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 this time, only a few Japanese ports are open to foreign ships (Hakodate, Nagasaki, Yokohama), and Tsushima is 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 aggression.
Japan receives British help to support its policy.
As tension rises, a second Russian ship arrives, and requests are made by the Russians to build a landing base and to receive supplies.