“Yes, I know that the timing for the attack was tight but do not recall all the reasons why. I believe that the Japanese were desperate to attack the Dutch and British in South Asia to get at oil and they may have had weather constraints since the Japanese had to sail from the North to surprise the US.”
The Japanese had considered two war strategies described as going North or going South. One faction of the Japanese leadership argued for going North, meaning to attack the Soviet Union to conquer its territories while it was engaged with Germany in a losing war. Another faction of the Japanese leadership argued for going South in an offensive against the ABDA (American, British, Dutch, and Australian) alliance in a bid to conquer what they described as the Southern Resource Area. Because going North against the Soviets did not promise the conquest of substantial resources in oil, rubber, bauxite, food, and other items needed to sustain future military and naval campaigns, those arguing to go South and conquer the Southern Resource Area abundant in those resources won the argument.
The timing of the war and offensives to conquer the Southern Resource Area ee dictated by a number of factors.
The effective ending of the Washington Naval Limitations Treaty by Germany and Japan followed by the American appropriations for a massive new U.S. Navy construction programme for larger modern battleships, aircraft carriers, fleet submarines, and other warships established what the Japanese leadership believed was a limited window of opportunity for the Japanese to exploit a brief period where its warships could dominate or compete with the U.S. Pacific Fleet between 1941 to 1944.
The United States had long ago planned to grant independence to the Philippines by 1945-46. In preparation for that future independence, former U.S. Army Chief of Staff General MacArthur had been assigned the task of training and equipping a Filipino army. The first military training classes commenced in September 1941 and was scheduled for graduation by April 1942. The Japanese leadership regarded the organization of a Filipino army as an intolerable threat for their planned conquests of the Southern Resource Area and the defense of the shipping lanes from those conquered lands back to the Japanese Home Islands. Consequently, the Japanese advanced their plans for their offensives from Spring 1942 to November or December 1941 in part to disrupt the organization of a Filipino army capable of interfering with the Japanese war plans for conquest.
Another factor in timing Japan’s plans for conquests were the embargoes the ABDA alliance placed upon such war material and resources as oil, steel, iron, nickel, rubber, and more. The Japanese leadership calculated the Japanese Navy, air forces, and industries had enough oil for another couple of years before its military and naval forces would be compelled to suspend combat operations to provide enough resources to sustain the civilian economy. Given the upcoming American rearmament of its naval and military forces, the Japanese leadership calculated the conquests had to be completed no later than 1942-43 in order to sustain the offensive capabilities of its armed forces.
December 1941 just happened to be the earliest time period Japan could become prepared to launch its Pacific War.
“It is just hard for me to reconcile that someone who was purported to be such a brilliant admiral particularly in regards to his understanding of the importance of aircraft carriers could miss this.”
Yamamoto certainly did not miss the importance of destroying the American aircraft carriers. The plan to strike the U.S. Pacific Fleet while anchored in Pearl Harbor on a Sunday instead of any other day of the week was conceived for the specific purpose of catching one or more of the U.S. aircraft carriers in port at the time of the Japanese air attack. The idea failed largely because of the inability to change attack dates and sheer chance. The U.S.S. ENTERPRISE would have been caught in port at Pearl Harbor on Sunday if it had not had to slow down for its escorting destroyers. Bad weather and seas interfered with the ability of the ENTERPRISE to refuel its destroyers while underway, so the destroyers had to slow their engines to conserve fuel. Even so, they were so low in fuel some were in danger of being towed into port. ENTERPRISE’s delay in returning to Pearl Harbor saved it from being attacked in port.
The U.S.S. LEXIGNTON and other aircraft carriers were also absent from Pearl Harbor on Sunday due to their respective non-routine missions, including missions ferrying combat aircraft to the American garrisons on Midway Island and Wake Island.
Yamamoto and his staff were obligated to coordinate the strike to occur concurrently with all of the other Japanese offensive operations in the other theaters from India, Southeast Asia, China, the South Pacific, Central Pacific, and north Pacific theaters of operations. Accordingly, the date of the strike on Pearl harbor once set could not be changed without also changing the dates and times of the entire war. It just so happened by chance that the Americans atypically assigned non-routine missions for most its the aircraft carriers for the same Sunday the Japanese raid and the entire war had been pre-scheduled.