50 PEARL HARBOR ATTACK [Blank] PEARL HARBOR ATTACK 51 PART II THE JAPANESE ATTACK AND ITS AFTERMATH 52 PEARL HARBOR ATTACK [Blank] PEARL HARBOR ATTACK 53 PART II. THE JAPANESE ATTACK AND ITS AFTERMATH FORMULATION OF THE PLAN AND DATE FOR EXECUTION [1] The evidence tends to indicate that a surprise attack on Pearl Harbor was originally conceived and proposed early in January of 1941 by Admiral Isoroku Yamamoto, commander in chief of the combined Japanese fleet, who at that time ordered Admiral Onishi, chief of staff of the Eleventh Air Fleet, to study the operation. Admiral Yamamoto is reported to have told Onishi about February 1, [2] "If we have war with the United States we will have no hope of winning unless the United States Fleet in Hawaiian waters can be destroyed." [3] During the latter part of August 1941, all feet commanders and other key staff members were ordered to Tokyo by Yamamoto for war games preliminary to formulation of final operation plans for a Pacific campaign which included a surprise attack on Pearl Harbor. A war plans conference was held continuously at the Naval War College, Tokyo, from September 2 to 13, and on September 13 an outline incorporating the essential points of a basic operation order, which was later to be issued as *Combined Fleet Top Secret Operation Order No. 1*, was completed. On November 5, 1941, this operation order, which included detailed plans for the surprise attack on Pearl Harbor, was promulgated to all fleet and task force commanders. The date, November 5, is in consequence properly to be regarded as the date on which the plan for the attack on Pearl Harbor was completed. Under the heading "Preparations for the outbreak of war," operation order No. 1 provided that " when the decision is made to complete over- all preparations for operations, orders will be issued establishing the *approximate* date (Y-day) for commencement of operations and announcing 'first preparations for war.' " The order further provided that "the time for the outbreak of war (X-day) will be given in an Imperial general headquarters order." The details of the plan with respect to the Pearl Harbor attack were worked out by members of the naval general staff operations section, combined fleet operations staff, and first air fleet operations staff. Admiral Yamamoto on November 7 issued combined fleet top secret operation order No. 2 relating: "First preparations for war. Y-day will be December 8." Consistent with the definition of Y-day as given in operation order No. 1, December 8 (December 7, Honolulu time) was thus established only as the approximate date for commencement of operations. The imperial general headquarters, [1] The chief sources of information concerning the attack are translations of captured Japanese documents, interrogations of prisoners of war, and reports submitted by general headquarters, supreme commander for the Allied Powers, comprising questionnaires filled out since VJ-day by former members of the Japanese naval high command. See committee exhibits Nos. 8, 8A, 8B, 8O, and 8D. For purposes of convenience, the term Hawaii is used throughout this report as synonymous with the Territory of Hawaii. [2] Unless otherwise stated the time indicated is Tokyo time. To obtain the corresponding time in Washington and Honolulu, 14 hours and 19 1/2 hours, respectively, should be subtracted from Tokyo time. See committee exhibit No. 6, item 4. [3] See committee exhibit No. 8D. 54 PEARL HARBOR ATTACK however, issued an order on December 2 stating, "The hostile actions against the United States of America shall be commenced on December 8," thereby announcing X-day as defined in operation order No. 1. The tentative approximate date for the attack selected on November 7 and defined as Y-day in consequence became the final precise date, X-day. The Japanese imperial headquarters navy section, in discussions prior to November 7, generally recognized December 8 as a propitious date from an operational viewpoint and decided upon this date in conjunction with the leaders of the combined fleet. It was noted that from the standpoint of a dawn attack in the Hawaiian area December 10 would have been suitable in view of the dark of the moon. But it was expected the United States Pacific Fleet, in accordance with its custom during maneuvers, would enter Pearl Harbor on Friday and leave on Monday. Sunday, December 8, was therefore decided upon with the understanding that, to assure the success of the attack and still avoid a night attack, the take-off time of the attacking planes was to be set as near to dawn as possible; that is, approximately 1 hour before sunrise. An imperial naval order issued on December 1 stated: "*Japan * * * has reached a decision to declare war ors the Untied States of America, British Empire, and the Netherlands.*" [4] NATURE OF THE PLAN Three possible avenues in approaching Hawaii for the attack presented themselves: The northern course, which was used; a central course which headed east following the Hawaiian Islands; and a southern route passing through the Marshall Islands and approaching from the south. Because of the absolute requirement that the element of surprise be a factor in the attack, the northern course was selected since it was far from the United States patrol screen of land-based aircraft, and there was little chance of meeting commercial vessels. Screening destroyers were to be sent ahead of the Japanese Fleet and in the event any vessels were encountered the main body of the force was to make a severe change in course and endeavor to avoid detection. If the striking force was detected prior to the day before the attack, it was planned to have the force return to Japanese waters without executing the attack. On the other hand, should the force be detected on the day before the attack, the question of whether to carry home the attack or to return was to be resolved in accordance with local conditions. [5] If the attack should fail, the main force of the Japanese Navy, located in the Inland Sea, was to be brought out to the Pacific in order to return the striking force to home waters. According to Japanese sources interviewed since the defeat of Japan, the sources of information employed in planning the attack included public broadcasts from Hawaii; reports from naval attaches in the Japanese Embassy, Washington; public newspapers in the United States; reconnaissance submarines in Hawaiian waters prior to the attack; and information obtained from crews and passengers [4] See committee exhibit No. 8D. [5] Had the American Fleet left port it is reported that the Japanese force would have scouted an area of about 300 miles around Oahu and was prepared to attack. If the American Fleet could not be located the striking force was to withdraw. See committee exhibit No. 8. PEARL HARBOR ATTACK 55 of ships which had called at Honolulu in mid-November. [6] It also appears that Japan was receiving the same type of espionage information from its Honolulu consul as from other Japanese diplomatic establishments. [7] The Japanese plan of operation was predicated on certain assumptions with respect to the United States Pacific Fleet: (1) That the main body of the fleet would be at anchor within Pearl Harbor on Sunday, December 7, Hawaii time; (2) that a carrier could be moved from Japanese home waters across the Pacific to within striking distance of the main islands of the Hawaiian group without undue risk of detection by American defensive reconnaissance; (3) that should the two foregoing assumptions be in error, a reserve group of heavy naval units could sortie from the Inland Sea to give support to the carrier striking force in a decisive engagement with the American Fleet (4) that a powerful carrier air strike against the American forces based in Hawaii could, if tactical surprise were effective, achieve the strategic result of crippling the American Fleet, and (5) that such a strike could achieve also the destruction of American land-based air power and thus permit the Japanese striking force to withdraw without damage. Incident to preparations and discussions on September 6 and 7 relating to operation order No. 1, it was decided that no landing on the island of Oahu should be attempted since (1) it would have been impossible to make preparations for such a landing within less than a month after the opening of hostilities; (2) it was recognized that the problems of speed and supply for an accompanying convoy would have rendered it unlikely that the initial attack could be accomplished without detection; and (3) insuperable logistic problems rendered landings on Oahu impractical. In formulating the final plans it was determined that a torpedo attack against ships anchored in Pearl Harbor was the most effective method of putting the United States Pacific Fleet in the Hawaiian area out of action for a long period of time. Two obstacles to a torpedo attack were considered: The fact that Pearl Harbor is narrow and shallow; and the fact that it was probably equipped with torpedo nets. In order to overcome the first difficulty it was decided to attach stabilizers to the torpedoes and launch them from extremely low altitude. Since the success of an aerial torpedo attack could not be assured because of the likelihood of torpedo nets a bombing attack was also to be employed. [6] It is reported that Japanese agents in Hawaii played no part in the attack. See committee exhibit No. 8. The location of the anchorages shown on the maps recovered from the attacking force was determined on the basis of the indicated sources beginning in the early part of 1941. It has been reported that the intelligence section of the Japanese naval general staff was having a most difficult time judging the habits, strength, and security situations of the American Fleet in the Hawaiian ea. Because of this, the intelligence section had been for years compiling material by carefully collecting, making into statistics, and analyzing bits of information obtained from naval officers at Washington, newspapers and magazines published in America, American radio broadcasts signal intelligence, passengers and crews of ships stopping over at Honolulu, other foreign diplomatic establishments, commercial firms, and similar sources. According to the signals of the American ships, the number of ships and small craft of the Pacific Fleet anchored in Pearl Harbor or out on training was deduced. By combining the flying time (judged according to signal situations) of airplanes shuttling between bases and aircraft carriers out on training missions, and the location of United States Fleet units as seen by passengers and crews of ships stopping over at Honolulu, the training areas of the fleet were determined. The zone, time, etc., of airplanes at Hawaii were deduced in the same way. From newspapers and magazines published in the United States, material was obtained for deduction of America's war preparation, progress and expansion of military installations, location and capabilities of warships and airplanes, Army strength at Hawaii, Panama, the Philippines, and other places. It is reported from Japanese sources that the reports from foreign diplomatic establishments and commercial firms in foreign countries were regarded as not important enough from the standpoint of intelligence to have a "special write-up, and were considered on their own merits." See committee exhibit No. 8C. [7] See committee exhibit No. 2. 56 PEARL HARBOR ATTACK The complete plan of the attack was known in advance to members of the Navy general staff, the commander in chief and chiefs of staff, and staff members of the combined fleet headquarters and first air fleet headquarters. Portions of the plan were known to the Navy Minister, the Navy Vice Minister, and other ranking naval officers. It has been reported that the Japanese Emperor knew in advance only the general outline of the plan and that none of the Japanese officials in the United States, including Ambassadors Nomura and Kurusu, knew anything concerning the plan prior to the attack. The aims of the entire Japanese campaign, including the attack on Pearl Harbor, were based on the desire for military conquest, security, and enhancement of the Empire by occupation of areas rich in natural resources. With respect to the Pearl Harbor attack, operation Order No. 1 stated: "In the east the American Fleet will be destroyed and American lines of operation, and supply lines to the Orient, will be cut. Enemy forces will be intercepted and annihilated. Victories will be exploited to break the enemy's will to fight." [8] DEPARTURE FOR THE ATTACK On or about November 14 [9] units of the Pearl Harbor attacking force were ordered to assemble in Hitokappu Bay, located in the Kurile Islands, [10] this operation being completed by November 22. On November 25 the commander in chief of the combined Japanese Fleet issued the following order: [11] (a) The task force, keeping its movements strictly secret and maintaining close guard against submarines and aircraft, shall advance into Hawaiian waters and upon the very opening of hostilities, shall attack the main force of the United States Fleet in Hawaii and deal it a mortal blow. The first air raid is planned for dawn of X-day (exact date to be given by later order). Upon completion of the air raid the task force, keeping close coordination and guarding against enemy counterattack, shall speedily leave the enemy waters and then return to Japan. (b) Should it appear certain that Japanese-American negotiations will reach an amicable settlement prior to the commencement of hostile action, all the forces of the combined fleet are to be ordered to reassemble and return to their bases. (c) The task force shall leave Hitokappu Bay on the morning of November 26 and advance to 42 N. And 170 E. (standing-by position) on the afternoon of December 4, Japan time, and speedily complete refueling. (The actual time of departure was 9 a. M. November 26, Japan time-1:30 p. m., November 25, Hawaii time.) Since the American Fleet and air power based in the Hawaiian area were the only obstacles of consequence, a major task force built around a carrier striking group was considered essential to conducting a successful surprise attack. Accordingly, the striking force consisted of 6 aircraft carriers, including the Akagi, the flagship of Admiral Nagumo; 2 battleships, 2 heavy cruisers, 9 destroyers, 3 submarines, 8 train vessels, and approximately 360 planes, which [8] Other factors included (1) rendering impotent the United States Pacific Fleet in order to gain time and maintain freedom of action in the South Seas operation, including the Philippine Islands, and (2) the defense of Japan's mandated islands. See committee exhibit No. 8. [9] Other information obtained indicates that the commander in chief of the combined fleet issued the following order on November 7 ("The task force, keeping its movements strictly secret will assemble in Hitokappu Bay by November 22 for refueling." Committee exhibit No. 8. [10] Also referred to as Tankan Bay (Etorfu Islands, Kuriles), and Tankappu-Wan. [11] See committee exhibit No. 8. PEARL HARBOR ATTACK 57 participated in the attack. Other submarines had proceeded from the Inland Sea independent of the striking force. [12] At 9 a. m., November 26, [13] the Japanese Fleet departed under complete radio silence from Hitokappu Bay for its destination 200 miles north of Oahu. Held down by the low speed of the train vessels and the need for fuel economy, the force cruised eastward at 13 knots. Lookouts were posted, but no searches or combat air patrols were flown. [14] The anticipated difficulty in refueling at sea because of weather conditions did not materialize, since the weather proved uniformly calm. On or about December 2 all ships were darkened, and on December 4 the rendezvous point (42 north; 170 east) was reached and the combat ships fueled to capacity from the tankers. The cruise had been entirely uneventful, no planes or ships having been sighted. [15] The green light to execute the attack had been sent by Admiral Yamamoto from his flagship, the Yamato, on December 2. The message was "Niita Kayama Nobore," translated "Climb Mount Niitaka," which was the code phrase meaning "proceed with attack." [16] EXECUTION OF THE ATTACK [17] AIR PHASE On the night of December 6-7 (Hawaii time) the "run-in" to a point 200 miles north of Oahu was made at top speed, 26 knots. Beginning at 6 a. m. and ending at 7:15 a. M., December 7, a total of ;60 planes were launched in three waves. The planes rendezvoused to the south and then flew in for coordinated attacks. In addition to the attack planes, it is reported that two type Zero reconnaissance [12] The following allocation of forces for the attack was made (see committee exhibit No. 6, item 17): STRIKING FORCE Commanding Officer: CinC 1st Air Fleet, Vice Admiral Chuichi NAGUMO BatDiv 3 (1st Section) (HIEI, KIRISHIMA), 2 BB CarDiv 1 (KAGA, AKAGI) CarDiv 2 (HIRYU, SORYU) CarDiv 5 (SHOKAKU, ZUIKAKU) 6 CV CruDiv 8 (TONE, CHIKUMA), 2 CA DesRon 1 (ABUKUMA, 4 DesDivs), 1 CL, 16 DD. 8 Train Vessels. ADVANCE EXPEDITIONARY FORCE Commanding Officer: CinC 6th Fleet, Vice Admiral Mitsumi SHIMIZU. ISUZU, YURA, 2 CL. KATORI, 1 CL-T I-class submarines (including SubRons 1, 2, 3) (I-1, 2, 3, 4, 5, 6, 7, 16, 17, 18, 20, 22-24, 68, 69, 74), 20 SS. Midget submarines, 5 M-SS. 6 Train Vessels. [13] The corresponding time in Washington would be 7 p m. November 25. [14] A very close watch was kept on Hawaiian broadcasts by Commander Ono, staff communication officer of the striking force. Admiral Nagumo and his staff believed that they could sense from these broadcasts whether or not the forces on Oahu had an inkling of the impending attack. They felt they could judge the tenseness of the situation by these broadcasts. Since stations KGU and KGMB were going along in their normal manner, Admiral Nagumo felt that American forces were still oblivious of developments. For several days prior to the attack the Jap force had been intercepting messages from our patrol planes. They not broken the code, but they had been able to plot in their positions with radio bearings and knew the number of our patrol planes in the air at all times and that they were patrolling entirely in the southwestern sector from Oahu. Committee exhibit No. 8D. [15] To disguise the move against Pearl Harbor the main Japanese force in the Inland Sea area and the land based air units in the Kyushu area carried on deceptive communications, and deceptive measures were taken to indicate that the task force was still in training in the Kyushu area. See committee exhibit No, 8. [16] Committee exhibit No. 8d. [17] The time hereafter indicated is Hawaiian time unless otherwise specified. 58 PEARL HARBOR ATTACK seaplanes were launched at approximately 5 a. m., December 7, to execute reconnaissance of Pearl Harbor and Lahaina Anchorage just before the attack, reaching their destination about 1 hour before arrival of the attack planes. [18] The Japanese aircraft participating in the operation included 81 fighters, 135 dive bombers, 104 horizontal bombers, and 40 torpedo bombers. Five distinct phases were noted in the execution of the attack, as recounted from the Navy point of view: [19] Phase I: Combined torpedo plane and dive bomber attacks lasting from 7:55 a. m. to 8:25 a. m. Phase II: Lull in attacks lasting from 8:25 a. m. to 8:40 a. m. Phase III: Horizontal bomber attacks extending from 8:40 a. m. to 9:15 a. m. Phase IV: Dive bomber attacks between 9:15 a. m. and 9:45 a. m. Phase V. Warning of attacks and completion of raid after 9:45 a. m. The primary objectives of the Japanese during the raid were the heavy combatant ships and aircraft. Damage to the light forces and the industrial plant was incidental to the destruction or disablement of the heavy ships and aircraft based ashore. In the statement submitted for the consideration of the committee and in his testimony, Rear Adm. R. B. Inglis set forth a review of the various phases of the attack: [20] "Phase I: 7:55-8:25 a. m. Combined Torpedo Plane and Dive Bomber Attacks "The beginning of the attack coincided with the hoisting of the preparatory signal for 8 o'clock colors. At this time (namely, 7:55 a. m.) Japanese dive bombers appeared over Ford Island, and within the next few seconds enemy torpedo planes and dive bombers swung in from various sectors to concentrate their attack on the heavy ships moored in Pearl Harbor. It is estimated that nine planes engaged in the attack on the naval air station on Ford Island and concentrated on the planes parked in the vicinity of hangar No. 6. "At the time of the attack Navy planes (patrol flying boats, float planes, and scout bombers, carrier type) were lined up on the field. These planes caught fire and exploded. Machine-gun emplacements were set up hastily and manned, although the return fire from shore on Ford Island was pitifully weak. Then, as suddenly as they had appeared, the Japanese planes vanished. No further attack on this air station was made during the day. Except for a direct hit on hangar No. 6 resulting from a bomb which was apparently aimed at the battleship California and which fell short, the damage to the station itself was comparatively slight. However, 33 of the Navy's best planes out of a total of 70 planes of all types were destroyed or damaged. "As soon as the attack began, the commander of patrol wing 2 broadcasted from 1. Ford Island the warning: "Air raid, Pearl Harbor. This is *not* drill." This warning was followed a few minutes later by a similar message from the commander in chief, United States Fleet. "At approximately the same time that the Japanese dive bombers appeared over Ford Island, other low-flying planes struck at the Kaneohe Naval Air Station on the other side of the island. The attack was well executed, with the planes coming down in shallow dives and inflicting severe casualties on the seaplanes moored in the water. Machine guns and rifles were brought out, and men dispersed to fire at will at the low- flying planes. After a period of 10 to 15 minutes, the attacking planes drew off to the north at a low altitude and disappeared from sight. Several other contingents of bombers passed over, but none dropped bombs on Kaneohe Bay. "About 25 minutes after the first attack, another squadron of planes, similar to one of the Navy's light bomber types, appeared over Kaneohe and commenced bombing and strafing. No. 3 hanger received a direct hit during this attack, and [18] See committee exhibit No. 155 [19] For a description of the attack as obtained from Japanese sources since VJ-day, see committee exhibits Nos. 8 and 8B, p. 10. [20] Committee record, pp. 85-103. PEARL HARBOR ATTACK 59 our planes in the hangar were destroyed. The majority of the casualties suffered at Kaneohe resulted from this attack. Most of the injured personnel were in the squadrons attempting either to launch their planes or to save those planes not as yet damaged. When the enemy withdrew, some 10 to 15 minutes later, salvage operations were commenced, but it was too late to save No. 1 hangar, which burned until only its steel structural work was left. Only 9 out of the 36 planes at Kaneohe escaped destruction in this attack; 6 of these were damaged, and 3 were in the air on patrol south of Oahu. "Meanwhile, the Marine air base at Ewa was undergoing similar attack. Apparently the attack on Ewa preceded that at Pearl Harbor by about 2 minutes. It was delivered by 2 squadrons of 18 to 24 single-seater fighter planes using machinegun strafing tactics, which came in from the northwest at an altitude of approximately 1,000 feet. These enemy planes would descend to within 20 to 25 feet of the ground, attacking single planes with short bursts of gunfire. Then they would pull over the treetops, reverse their course and attack from the opposite direction. Within less than 15 minutes, all the Marine tactical aircraft had been shot up or set on fire. Then the guns of the enemy fighters were turned upon Navy utility aircraft, upon planes that had been disassembled for repair, and upon the marines themselves. "Effective defense measures were impossible until after the first raid had subsided. Pilots aching to strike at the enemy in the air viewed the wreckage which until a few minutes before had been a strong air group of Marine fighters and bombers. Altogether 33 out of the 49 planes at Ewa had gone up in smoke. Some marines, unable to find anything more effective, had tried to oppose fighter lanes with pistols, since the remaining 16 planes were too badly damaged to fly. "Although in phase I of the attack on the ships at Pearl Harbor Japanese dive bombers were effective, *the torpedo planes did the most damage*. They adhered strictly to a carefully laid plan and directed their attacks from those sectors which afforded the best avenues of approach for torpedo attack against selected heavy hip objectives. Thus they indicated accurate knowledge of harbor and channel depths and the berths ordinarily occupied by the major combatant units of the fleet. At least in the great majority of eases, the depth of water in Pearl Harbor did not prevent the successful execution of this form of attack. Shallow dives of the torpedoes upon launching were assured by the use of specially constructed wooden fins, remnants of which were discovered on enemy torpedoes salvaged after the attack. "Four separate torpedo plane attacks were made during phase I. The major attack was made by 12 planes, which swung in generally from the southeast over the tank farm and the vicinity of Merry Point. After splitting, they launched their torpedoes at very low altitudes (within 50 to 100 feet of the water), and from very short distances, aiming for the battleships berthed on the southeast side of Ford Island. All the outboard battleships (namely, the Nevada, Arizona, West Virginia, Oklahoma, and California) were effectively hit by one or more torpedoes. Strafing was simultaneously conducted from the rear cockpits. A recovered unexploded torpedo carried an explosive charge of 1,000 pounds. "During the second of these attacks, the Oklahoma was struck by three torpedoes on the port side and heeled rapidly to port, impeding the efforts of her defenders to beat off the attackers. "The third attack was made by one torpedo plane which appeared from the west and was directed against the light cruiser Helena and the minelayer Oglala both of which were temporarily occupying the berth previously assigned to the battleship Pennsylvania, flagship of the Pacific Fleet. One torpedo passed under the Oglala and exploded against the side of the Helena. The blast stove in the side plates of the Oglala. Submersible pumps for the Oglala were obtained from he Helena but could not be used since no power was available because of damage to the ship's engineering plant. "The fourth wave of five planes came in from the northwest and attacked the seaplane tender Tangier, the target ship Utah, and the light cruisers Raleigh and Detroit The Raleigh was struck by one torpedo, and the Utah received two hits in succession, capsizing at 8:13 a. m. At first it was feared that the Raleigh would capsize. Orders were thereupon given for all men not at the guns to jettison all topside weights and put both airplanes in the water. Extra manila and wire lines were also run to the quays to help keep the ship from capsizing. "The Utah, an old battleship converted into a target ship, had recently returned from serving as a target for practice aerial bombardment. As soon as she received her torpedo hits, she began listing rapidly to port. After she had listed to about 40 degrees, the order was given to abandon ship This order was