Exhibit 40 makes good reading and I made a copy to keep with my Prange book. However, delivering an attack by twelve squadrons would require every CV the Japanese had and then the decks would be empty of aircraft leaving nothing to defend the task force or launch a counter attack. The Japanese added two CVL’s for Pearl Harbor. When Yamamoto took six carriers he left the complex and extensive southern operations almost totally dependent on land based aircraft. Those folks were not happy and had opposed him vigorously.
In stating the maximum, the writer makes a speculation unexampled by actual operations or any war gaming. I remember a 1930’s Navy exercise involving attack by a single carrier on the Panama Canal, so I am willing to believe that my source on the subject of multiple carrier operations has done his homework. I said the attack was possible and therefore plausible, but not probable. Sorry about that terrible sentence, but must have been just too tired to wordsmith it properly.
Naval History: Pearl Harbor’s Overlooked Answer
http://www.usni.org/magazines/navalhistory/2011-12/pearl-harbors-overlooked-answer
Yes, we can certainly agree on point One. It agrees to my first post which said, “Revisionists offer arguments that FDR, Cordell Hull, and George Marshall foreknew the Pearl Harbor attack. These authors review historical events for those few data points that indicate an overwhelming attack. However, living history forward means accumulating and discerning patterns from 10,000’s of data points coming from humint, radio traffic analysis, code breaking, etc…..
The attack was a truly unexpected and improbable use of the Japanese air fleet.”
Japan's attack on Pearl Harbor was driven by compelling strategic logic that was well-known for many years to naval planners in both Japan and the US. Unless the US Pacific fleet was taken out at the outset of the war, it would endanger Japan's conquest of East Asia, perhaps even denying Japan the vital oil fields of the Dutch East Indies.
Long before the vulnerability warned of in Exhibit 40, a Japanese carrier attack on Pearl Harbor was anticipated as a distinct possibility. In the late 1920s, war games at the Japanese Navy War College examined a carrier attack against Pearl Harbor. In 1929, then Captain Yamamoto lectured on the topic.
Of particular interest for our purposes, in 1932, widely-publicized US Pacific Fleet war exercises included a surprise carrier attack on Pearl Harbor carried out by Admiral Harry Yarnell -- on a Sunday morning no less. Prefiguring Japan's methods, in sailing from anchorages in California, Yarnell used radio silence, avoided shipping lanes and radar coverage, and had minimal escorts for his carrier striking force.
Not only was Washington well aware of Pearl Harbor's vulnerability to aerial attack, but so were the responsible naval officers on scene. Famously, on Dec. 2, 1941, Lt. Cmdr. Edwin T. Layton, the Pacific Fleet's intelligence officer, briefed Adm. Husband E. Kimmel, the Pacific Fleet commander, and presented a summary showing the approximate position of Japanese fleet units based on radio traffic.
Kimmel noted that there was no trace of either of the Imperial Navy's two carrier divisions. "You don't know where the carriers are?" "No, sir," replied Layton. "That's why I have 'Homeland waters' with a question mark. I don't know."
"You mean they could be coming around Diamond Head and you wouldn't know it?" The best reply that Layton could muster was that "I hope they would be sighted before now."
Was the Japanese attack on Pearl unexpected and improbable? Not really.