Why did Japan switch sides in World War 1?

Answer 1

Japan switched sides in World War 1 because of the Anglo-Japanese Alliance of 1902. This alliance was a military agreement between the United Kingdom and Japan, which stated that if either country was attacked by more than one power, the other would come to its aid. When World War 1 began, Japan saw an opportunity to expand its influence in the Pacific and declared war on Germany in August 1914.