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H-001-1: Pearl Harbor, 7 December 1941

Photo #: 80-G-K-13513 Pearl Harbor Attack, 7 December 1941
The forward magazines of USS Arizona (BB-39) explode after she was hit by a Japanese bomb, 7 December 1941. Frame clipped from a color motion picture taken from on board USS Solace (AH-5) (80-G-K-13513).

H-Gram 001, Attachment 1
Samuel J. Cox, Director NHHC
17 November 2016 

    The following is not intended to be a comprehensive account of Pearl Harbor, nor to whitewash the numerous errors of judgment and failures of process that occurred across all levels of the U.S. chain-of-command from the President to the tactical level.  Over time, the lessons of history tend to get distilled to a “bumper sticker” level, when the reality is far more complex and nuanced…and many times the conventional wisdom bumper sticker is just plain wrong.  There is no question that the United States and the Navy were not prepared for war, despite the fact that Navy leaders well-understood that U.S. diplomacy and economic embargos were pushing the Japanese toward initiating hostilities.  Navy leaders kept arguing for our diplomats to back off in order to buy more time. The commanders at Pearl Harbor were anticipating war far more than they were ever given credit for.  Hopefully this will stimulate you and your Sailors to want to know more. 

Things You Might Not Have Heard About Pearl Harbor:

    Vice Admiral Nagumo’s post-attack report stated that after the first five minutes U.S. AAA fire became so intense that it effectively negated the effect of surprise.  The fact that more Japanese planes weren’t shot down (9 on the first wave, 20 on the second wave) had more to do with the ineffectiveness of the weapons being used (.50 cal with too-short range, insufficient numbers of jam-prone 1.1” quad AAA guns, 5” guns that couldn’t elevate enough to counter dive bombers, large numbers of dud rounds) than due to surprise.  Japanese sources reported astonishment at the volume of fire put up by U.S. ships at Pearl Harbor, and the increasing intensity and accuracy was a major factor in Nagumo’s decision not to send a “third wave.”  The U.S. shipboard 5” guns, which became active mostly on the second wave, fired over 3,100 rounds, which actually accounted for the majority of U.S. civilian deaths (all the damage in Honolulu was from U.S. AAA returning to earth.)  The deficiencies in AAA were well known to Navy leaders in Washington, demonstrated in exercises at sea, but uncorrected until late 1942 with the introduction of Bofors 40mm, Oerlikon 20mm, and 5” with proximity fuses.  Due to the pre-war budget-driven paucity of “live-fire” training, the large number of defective rounds to came as an unpleasant surprise to the defenders at Pearl Harbor.  The Japanese torpedo planes that attacked Battleship Row (all in the first wave) also rolled in five minutes before planned, and even so, seven of the last nine were shot down; had they been on schedule, their losses to U.S. AAA would have been even greater.

    The known AAA deficiency of the U.S. ships (based on exercise experience) was a principle factor in why the battleships were in port rather than at sea (“Sunday” had little to do with it.)  The two U.S. carriers (USS Lexington (CV-2) and Enterprise (CV-6)) in the mid-Pacific were away on higher-priority national tasking to deliver U.S. Marine aircraft (stripped from Pearl Harbor defenses) to Midway and Wake Island to support the transit of B-17 bombers to the Philippines in a hastily conceived change of national strategy to use bombers to deter Japanese attack against the Philippines.  The original orders called for the carriers to carry and launch U.S. Army Air Force fighters (also stripped from Pearl Harbor) but Admiral Kimmel succeeded in convincing Washington that was a dumb idea.  Without carrier air cover, the battleships at sea were considered to be highly vulnerable to both air and submarine attack, and the lack of carrier air cover was the principle reason Kimmel brought the fleet in, and in the event the ships were sunk, they wouldn’t be lost in deep water with most of their crews.  In Pearl Harbor, the responsibility of air defense was with the Army (Navy was responsible for long range reconnaissance.)  The Army’s capability to defend Pearl Harbor against air attack was a known serious deficiency, one that the Army commander in Hawaii, General Short, had lobbied hard to correct but had been overridden by Washington due to higher priority elsewhere.  Despite knowing this, Kimmel reasoned that having the ships in port with some air cover was better than being at sea with no air cover (which disabuses the notion that “battleship admirals” just didn’t get it.)

    Because of the known deficiency in Army air defense (minimal AAA and many obsolete aircraft) Kimmel directed the ships in port maintain a higher status in AAA readiness then they would normally have been at.  Although the stories of ammunition being “locked up” (which was true for ships in repair status) have become common lore, a quarter of the fleet’s .50 cal AA were manned and ready, and reacted almost immediately.   The 5” guns came on line quickly, but too late to counter the torpedo bombers which led the first wave (which were most vulnerable to fire from the 5” guns) and largely ineffective against the dive and high-level bombers.  For every story of naval personnel being dumfounded that they were are under attack, there are more where naval personnel instantly grasped what was happening; the signal for air attack was being hoisted as the first bomb was falling on Ford Island, and most ships began responding with the capability they had almost immediately (although the gun crews were actually well-trained and drilled, the .50 cal were just not particularly effective).  The ships were more fully manned than they normally would have been; 70% of the officers and almost all enlisted were aboard ships in operational status.  (Thanksgiving leave and liberty had been cancelled; Kimmel’s staff had been at work late Saturday – the fleet was not in “holiday routine.”  Of note, after Admiral Nimitz assumed command, he carefully reviewed Admiral Kimmel’s inport air defense plan and chose not to change any of it, reasoning that it was as well-thought out as could be given the system limitations.

    Admiral Kimmel, and his predecessor, Admiral Richardson, were well aware that Pearl Harbor was potentially vulnerable to air attack (contrary to popular lore).  In at least four major fleet battle problems in the 1920’s and 1930’s (and numerous smaller exercises,) U.S. carriers had “attacked” Pearl Harbor and achieved surprise every time.   Admiral Richardson was fired by President Roosevelt for vociferously arguing that putting the Pacific Fleet in Pearl Harbor was a provocation and a vulnerability rather than a deterrent to the Japanese, and also lacked the support/supply infrastructure of the Pacific Fleet’s then home ports of San Pedro and Long Beach.  The Pacific Fleet had deployed to Hawaii as part of an exercise in 1940 and had been ordered by President Roosevelt to stay (Imagine three carriers going out on RIMPAC and being directed to stay in Hawaii indefinitely, with no families or preparation and insufficient support infrastructure.)   When Kimmel assumed command, he lobbied continuously and vigorously for more long-range reconnaissance, more air defense capability, and even barrage balloons and torpedo nets.  Almost none of what Kimmel requested was forthcoming, due to the higher priority of the Atlantic, or because the U.S. Navy didn’t have the capability yet.

    The critical thing that Admiral Kimmel did not know (and no American knew) was that only at the 11th hour in late October had the Japanese figured out, through extensive trial and error, a torpedo fin configuration that would enable torpedoes to be launched from aircraft in water as shallow as Pearl Harbor.  Kimmel anticipated a bomb threat, that barring a lucky hit like the one on the Arizona, could damage a battleship, but wasn’t considered near as lethal as a torpedo.  Kimmel also was not anticipating an attack of the scale of Pearl Harbor; the first time the Japanese ever launched a six-carrier strike was 7 Dec 1941, even they hadn’t practiced it.  Kimmel, along with everyone else in the U.S. Navy at the time, “mirror imaged” Japanese capability in believing their carriers would operate as ours, in single carrier task groups.  Many others woefully under-estimated Japanese capability, e.g. since our torpedoes couldn’t be dropped in such shallow water, how could the Japanese with their “inferior” technology possibly do it?

    Also contrary to lore, Kimmel and most other senior Navy leaders were very cognizant of the threat posed by carrier aviation.  As early as 1916, the Navy General Board (the group of senior Navy Admirals that advised the Secretary of the Navy – eventually supplanted by the OPNAV staff) stated that whoever controlled the air at sea had a decisive advantage.  During exercises in the 1930’s however, the carriers were always “sunk,” because they were highly vulnerable to the opposing carrier.  The carriers were essentially viewed as a prizefighter with a knockout punch and a glass jaw, hence the continued focus on what the Navy viewed as a “balanced” fleet.  Even the Japanese still viewed their battleships as the decisive force, even after the attack.  Admiral Nagumo had a long list of reasons for not launching a third wave, but the primary one was that he did not know where the American carriers were and he assumed (erroneously) that we knew where he was, which made him acutely vulnerable to surprise attack by the American carriers.

    The location of the Japanese carriers, particularly the big fleet carriers, was the highest priority for U.S. Naval Intelligence in the Pacific in the year leading up to Pearl Harbor, and the intelligence organization had gone to 24/7/365 manning (normal now, but unheard of then) months before the attack in response to rising tensions.  In the weeks before the attack, U.S. naval intelligence knew that we had lost track of the carriers, a fact of great concern, but something that had happened several times before for up to three weeks in the preceding year.  Although Japanese OPSEC was not perfect, they did not make themselves an easy target to track, ever.  Kimmel was so concerned about that lack of locating data on the carriers, that he personally visited the basement location of Station HYPO (under the command of Commander Joe Rochefort, who worked for OP-20G (in Naval Communications) in Washington, not for Kimmel) which was also unheard of, to understand exactly which codes were being read, and how the traffic analysis process worked.  At the morning staff meeting on 2 Dec 41, Kimmel said to his Fleet Intelligence Officer, LCDR Eddie Layton words to the effect, “do you mean to tell me the Japanese carriers could be rounding Diamond Head now and we wouldn’t know it?”  Layton responded with, “Yes, but I would have hoped they would have been spotted by now.”

    Two weeks prior the attack on Pearl Harbor, in response to rising tensions and even before the 27 November “War Warning” message, Admiral Kimmel directed the Pacific Fleet in Exercise 191.  The exercise plan called for the USS Lexington (acting as “Black” Force) to proceed two hundred miles north of Oahu and launch a strike against “White Base” (Pearl  Harbor) to test air defense reaction, and also to be on the lookout in case the Japanese might be in the area.  The exercise was cut short by directive from Washington to avoid any actions that might be interpreted by the Japanese as provocative, as Washington belatedly came to the conclusion that “buying time” was necessary.  Sources are in dispute as to whether Kimmel considered the north to be the primary threat sector, but this exercise (and the fact that previous exercise “surprise strikes” originated from the north, due to the far less dense shipping traffic) suggests that he did. As it turned out, the Japanese carrier force launched their strike from the same position as the Lexington did.

    The U.S. had broken the primary Japanese diplomatic code (“Purple”) and some lesser diplomatic codes.  The U.S. was in the process of breaking the Japanese General Naval Operating Code (then referred to as the “5 Num” code, and later retroactively as the JN-25 series.)  Sources conflict as to how much of the naval code the U.S. was reading before Pearl Harbor, but at best it wasn’t much.  The real point is that neither Kimmel nor Layton had access to Purple (also known as “Magic”) intelligence, other diplomatic intercepts, or any JN-25 intelligence that might have existed.  Some of the “conspiracy” books about Pearl Harbor postulate some sort of sinister intent on the part of Roosevelt, but the reality appears to be pure bureaucratic buffoonery.  Kimmel and Layton sensed that there was intelligence they were not getting (and Gen MacArthur and ADM Hart in the Philippines were,) especially after they got a couple Purple-derived messages by accident in July, and kept requesting to receive such intelligence.  The CNO, Admiral Stark (and others of the very few who were cleared) assumed that Kimmel was getting Purple traffic, or was told erroneously that he was, and no one followed up to be sure.  The Purple traffic was so tightly compartmented that no one actually had the big picture; the few senior leaders with access each sifted through hundreds of raw decoded intercepts, with no overall assessment.

    Within the Purple traffic, and the lesser diplomatic codes which were being decrypted very-time late, were plenty of indications that would have alerted Kimmel and Layton that Pearl Harbor was a target.  They did not receive any of it.  Prior to the attack on Pearl Harbor, there was a mountain of intelligence indicating that hostilities were imminent in the Far East between Japan and Britain and probably the United States.  In no message from Washington that Kimmel received, including the 27 November “War Warning,” was Pearl Harbor ever explicitly mentioned as a possible target.  The fact that Washington was also directing that fighters be stripped from Hawaii, over Kimmel’s and Short’s protests, strongly suggested to Kimmel that Washington was not concerned about an attack on Pearl Harbor.

    After the attack, the traditional American search for someone to blame (besides the Japanese) commenced in earnest.  Secretary of the Navy Frank Knox arrived soon after the attack to investigate.  The Army relieved General Short first, and in the spirit of “jointness” the Navy followed suit with Kimmel on 17 Dec 1941.  Kimmel expected to be relieved and revert to his “permanent rank” of two-star RADM. (It was fairly common for 3 and 4 stars to accept follow on positions at 2 star rank.  (RADM Claude Bloch, the Commander of the 14th Naval District (Hawaii) at the time of the attack, and who worked for both Kimmel and CNO Stark, had previously been the four-star Commander-in-Chief of the U.S. Fleet in 1938-40.))  Kimmel expected to be offered a follow-on job where he could contribute to the war, but that never happened and he eventually reluctantly resigned.  The Roberts Commission in 1942, which was the first of numerous investigations, was conducted with none of the rules of evidence or rights of the accused (e.g., right to review evidence against them, etc.) of a court martial, yet concluded that Kimmel and Short were guilty of “dereliction of duty,” resulting in a feeding frenzy by the press, public, and politicians.  With no opportunity to appeal, Kimmel was accused of failure to conduct adequate long-range reconnaissance, despite the fact that because of acute shortages of aircraft, trained crews and especially spare parts, Kimmel could only sustain a fraction of the coverage required – and the weather would have almost certainly prevented discovery of the Japanese anyway, even if Kimmel had been prescient enough to launch his few aircraft to the north on that particular morning.  Kimmel repeatedly requested a court-martial in order to defend himself, but was denied.  The primary reason was that a trial would have risked exposing the code-breaking effort that was considered (and really was) of paramount importance in winning the war.  Another unstated reason is that a trial would have risked the reputations of many senior military and government officials in Washington, who were far more culpable of the failures that led to surprise at Pearl Harbor than Kimmel was.

If by this point you think that Admiral Kimmel was treated unfairly, you are in the company of Admirals Zumwalt, Stockdale, Crowe, Hayward, Turner, Holloway, McKee, Lawrence, and 28 other 3-4 stars who signed a petition in 1991 to posthumously promote Rear Admiral Kimmel to Admiral.  So far it hasn’t happened.

I am not going to attempt to address the numerous conspiracy theories about Pearl Harbor (it is very much a cottage industry) other than to say that the vast majority are based on little-to-no actual evidence, usually taken out of context, and much speculation.  What can be said is that U.S. political and military leaders knew full well that the economic sanctions were backing the Japanese into a corner that would almost certainly result in an outbreak of war, and that the outbreak was imminent.  No one expected an attack on as devastating scale as that at Pearl Harbor.  Everyone grossly under-estimated Japanese capability and resolve, assuming that when the expected war came, we would easily clean their clock.

    It should also be noted that the Japanese made numerous errors of judgment as well, and but for some lucky breaks for the Japanese, the battle could have gone very differently.   The many Japanese mistakes included the Air Strike Commander, Fuchida, botching the signal to the strike force as to whether surprise had been achieved or not, and which plan (surprise or no surprise) to execute, which significantly effected timing and targets.  Most importantly, the Japanese apparently had no plan to take out the repair facilities, submarine base, and fuel storage facilities (all of which would play a critical role in their defeat) because most Japanese leaders believed the war would be too short for those to have an impact, and smoke from burning oil storage would just foul the range anyway.  The Japanese, too, grossly underestimated their enemy.

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Published: Wed May 08 09:39:18 EDT 2019