Feb 4-5, 1904 - Japan severs diplomatic relations with Russia.
Feb 8-9, 1904 - The Japanese surprise attack on Port Arthur.
April 25 - May 2, 1904 - Battle of the Yalu River
May 25-26, 1904 – The Battle of Nanshan.
August 10, 1904 - A Russian attempt to break out of a blockade fails.
Jan 22, 1905 – Bloody Sunday occurs in Russia.
Sept. 5, 1905 – Treaty of Portsmouth is signed.
1906-1920s - Japan leaves the League of Nations.
1931 - Japanese invade China.
1941 - The Pearl Harbor bombing occurs.
1937- 1940 - Japan joins WWII.
The Portsmouth Peace Treaty was arguably double edged, leading to peace between Russian and Japan, while simultaneously bolstering Japanese Imperialism. With the subsequent Great Depression, economic collapse increased tensions between Japan and the West, with tariffs being imposed on Japanese exports and unfair immigration laws.
The Japanese responded by invading Manchuria and demonstrating their military might. This drew ire from the United States, leading to Japan withdrawing from the League of Nations, joining the Axis in WWII, and subsequently bombing Pearl Harbor.
At the conclusion of WWII, Japanese Imperialism collapsed with Japan surrendering all of its acquired territory, and disbanding its military.