In 1887, the United States government obtained exclusive use of the inlet called Pearl Harbor, and the right to maintain a repair and coaling station for ships. The area was established as a naval base in 1908, and then in 1911 dredging of a channel from the sea was completed, across a sandbar and a coral reef at the mouth of the harbor. This made that channel accessible to the largest naval vessels, as it was now 35 feet deep, with a maximum depth of 60 feet. During the Japanese attack, this center for United States military action in the Pacific Ocean was nearly completely destroyed.
Between the middle of the 19th and the beginning of the 20th centuries, Japan looked to transform itself from a closed, feudal society into a modern industrial and military power. In the early 1930's, the Japanese army engaged in battles with the Chinese in Manchuria and prevailed. Because of their losses in these battles, Manchuria became a part of the Japanese political system. In 1937, conflict again began between Japan and China, this time near the Marco Polo Bridge in Beijing. This conflict led to a full-scale war known today as the Sino-Japanese War, which was one of the bloodiest in history and lasted until the defeat of Japan in 1945.
In 1939, World War II began with a string of German victories. These successes included the defeats of Poland, France and England. Many European nations that Germany now controlled had control of important colonial empires; the East Indies and Singapore in Southeast Asia. These empires were of interest to Japan