S. battle fleet near Pearl Harbor. The man to come up with the concept of a surprise attack was Admiral Yamamoto Isoroku. Yamamoto lived and studied in the United States and had great respect for the U.S. resources and industrial capability. Yamamoto wanted to avoid war with the U.S. if possible but knew if they did go to war, only a surprise attack would be effective. .
Japan had a strategic assessment as to what could happen after their attack of Pearl Harbor. One potential risk would be an unavoidable war with the U.S. and also a chance that the attack would keep the U.S. Fleet out of the war. Finally, Japan also hoped that the U.S. would agree to their territorial terms for peace or drain their naval resources from their involvement in Europe. A surprise attack on the U.S. battle fleet near Pearl Harbor would also allow Japan enough time to gather its resources base in Southeast Asia. Commander Nagumo ordered other forces to moved out of Japanese ports and steam toward British possessions in Malaysia and the Philippines. America's intelligence noticed the increased shipping activity from Japan and suspected that they was planning an aggressive course in the Southwest Pacific within the week. On November 27 the Navy issued a war warning to its Pacific's strongholds including Hawaii. However, none expected Japan to ever attack Pearl Harbor as it was an unlikely target being so far east. Even still Nagumo forces traveled towards Pearl Harbor, maintaining strict radio silence and also thanks to the weather, they managed to stay hidden near the entire ride. .
In the end, on December 7, 1941, Japan attacked Pearl Harbor which fully brought the U.S. to World War II. Japan's attack consisted of six carriers, a light cruiser, eleven destroyers and two heavy cruisers. They attacked from a remote naval base on the island of Etorofu and rendezvoused on December 7, 200 miles north of Pearl Harbor. At 0630 Nagumo launched over one-hundred-eighty-three aircraft from the naval base.
