ROMANOV FAMILY: RUSSO-JAPANESE WAR, 1904
The Russo-Japanese war began on January 26 (N.S. February 8) 1904. A Japanese fleet unexpectedly attacked Russian ships that were docked on the outer anchorage of Port Arthur, prior to any official declaration of war. As a result of this attack the most powerful ships of the Russian squadron had been taken out of commission. The official declaration of war between Japan and Russia occurred only on the 10th of February, 1904.
The main cause of Russo-Japanese War was the expansion of Russia to the East. However, the immediate cause was the annexation of the Liaodong Peninsula, previously captured by Japan. This triggered a military reform and the militarization of Japan.