Mr. MITCHELL. You explained in the beginning that Japanese times were given, but to just point it up, I am asking if that December 8 was December 7 Honolulu time.

Admiral INGLIS. That is correct. Unless I make some parenthetical, all times will be Tokyo time.

To repeat, in other words, the original tentative date-Y-day-and the final precise date-X-day-are, in fact, the same date.

In discussions prior to November 7, the Imperial headquarters navy section generally recognized December 8 as suitable from an operational standpoint and made the decision in cooperation with the leaders of the combined fleet. For a dawn attack in the Hawaiian area in December, the 10th would have been suitable from the standpoint of the dark of the moon.

Mr. MITCHELL. That you are taking from the documents; it is Japanese opinion?

Admiral INGLIS. That is correct. This is all oriented to the Japanese point of view.

[435]

However, it was expected that the United States Pacific Fleet, in accordance with its custom during maneuvers, would enter the harbor on Friday and leave on Monday-Hawaiian dates.

That is Friday and Monday, Hawaiian dates.

Therefore, Sunday-Hawaiian date-was decided on. In order 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-approximately 1 hour after sunrise.

Here I come to the deviation from the original script.

Mr. MITCHELL. A deviation resulting from these last documents? Admiral INGLIS. That is correct.

The following statement is made by a Japanese officer pilot who participated in the attack on Pearl Harbor:

On October 5, 1941, a meeting was called of all officer pilots of the carriers, aboard the Akagi in Shibushi Bay, by the chief of staff of the carriers, Rear Admiral Rynosuke Kosaka. About 100 attended. They were told, very secretly, that on "December 1941 (Japan time), a Japanese naval air force would strike the American Fleet at Hawaii." Grand Admiral of the Japanese Navy, Isoraku Yamamoto, also addressed the group, saying that, "Although Japan never wanted to fight [436] the United States, they were forced to because they would be defeated regardless, if the United States continued its aid to China and its oil embargo. The United States Fleet," he said, "was Japan's strongest enemy, so if they could strike it unexpectedly at Hawaii it would be 2 or 3 months before it could maneuver. By that time occupation of Borneo, the Philippines, Singapore. Java, and Sumatra would be complete."

The next title has to do with the date of leaving port.

It is reported that on or about November 14 CINC of the combined fleet ordered the units of the Pearl Harbor attacking force to assemble in Hitokappu Bay.

Commander Biard, will you point to Hitokappu Bay? That is the Island of Etorofu.

It is further reported that about November 21 the situation seemed to be approaching a stage where commencement of hostilities were inevitable. The navy section of the Imperial general headquarters therefore issued the following order:

The Commander-in-Chief of the Combined Fleet shall order necessary forces to advance to the area in which they are to wait in readiness and shall station them in such positions that, in the event of the situation becoming such [487] that commencement of hostilities be inevitable, they will be able to meet the situation promptly.

I would like to say at this time that upon introducing the subject of "Date of leaving port," I went back to the original script as prepared a few days ago.

On November 25 the commander in chief, combined fleet, issued the following order to the striking force, which had, since November 22, been assembled at Hitokappu Bay.

(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 aid 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 counter attack, 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.1

[438] (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.

Commander Biard, will you point to that position?

The actual time of departure was 9:00 a. m., November 26, Japan time-1:30 p. m., November 25, Hawaii time.

V. Date of instructions to execute plan: Combined fleet top secret operation order No. 2, issued by Admiral Yamamoto, commander-inchief of the combined fleet, and dated November 7, 1941 is the basic order or instruction to execute the detailed plan for the attack on Pearl Harbor.

On December 1 the Cabinet Council approved the commencement of hostilities against the United States. On the same day, an Imperial naval order issued on instruction by the Imperial general headquarters stated:

Japan, under the necessity of her self-preservation and self-defense, has reached a position (sic) to declare war on the United States of America.

On December 2 an Imperial naval order issued under instruction from the Imperial general headquarters stated:

The hostile actions against the United States of America shall be commenced on December 8.

There is no copy of this order available nor is there conclusive evidence that [439] it constitutes the formal X-day order referred to in operations order No. 1. Its effect, however, is clearly equivalent to the final determination of a specific time for the outbreak of the war, and it may be regarded therefore as a final determination of X-day.

VI. Details of plan: Hitokappu Bay was selected as the point of departure from Japan because it was recognized as the most suitable place for enabling the attacking force to meet any new developments in the situation as well as to keep its location and movements secret. In formulating final plans, it was decided that a torpedo attack against anchored ships in Pearl Harbor was the most effective method

1 See p. 205, infra, for correction by Adm. Inglis.

of putting the main strength of the United States Pacific Fleet in the Hawaii area out of action for a long period of time. The following two obstacles were considered:

(a) The fact that Pearl Harbor is narrow and shallow.

(b) The fact that Pearl Harbor was probably equipped with torpedo

nets.

In regard to point (a) it was planned to attach stabilizers to the torpedoes and launch them from an extremely low altitude.

In regard to point (b), since success could not be [440] counted on, a bombing attack was also employed.

I must deviate again from the text prepared the other day and refer to this last source received just yesterday.

Evidence indicates that as late as 29 November-Japan timethe Japanese force expected to find six United States carriers in Hawaiian waters; they were aware that the U. S. S. Saratoga was, in late November, on the west coast of the United States and also that the U. S. S. Enterprise would be "two or three days out of the attack." On 31 November, Japan time, when the striking force was well out to sea, it received a report that only one or two carriers were in Pearl Harbor. On December 6, Japan time, word was received that no carriers were in Pearl Harbor, but that 8 battleships and 15 cruisers were in the harbor. At a briefing, which took place on or about December 5, Japan time, each pilot was furnished a photograph of a map of Pearl Harbor on which each pilot made notes on courses, anchorage areas, or missions.

Now I return to the script of 2 or 3 days ago.

Three courses were considered for the Hawaii operation: The northern course which was actually 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. [441] Commander Biard, would you roughly indicate those three routes?

That would be the northern route (following Commander Biard's pointer), that would be the central route, through the Mandated Islands and the Hawaiian chain and the southern group just out of the Mandated Islands, up to Hawaii.

On the northern route, although it was far from the enemy, United States, patrol screen of land-based airplanes and there was little chance of meeting commercial vessels, the influences of weather and topography were important. Refueling at sea and navigation were difficult. On the central and southern routes the advantages and disadvantages were generally just the opposite to those of the northern route. Although it may be assumed that the central and southern routes would be preferable for the purposes of refueling at sea, the chances of being discovered by patrol planes were great because the routes lie near Wake, Midway, Palmyra, Johnston Islands, and so forth. Consequently, it was hardly expected that a surprise attack could be made. The ability to refuel and the necessity of surprise were the keys to this operation. If either of them failed, the execution of the operation would have been impossible. However, the refueling problem could be overcome by training. On the other hand, a surprise attack under all circumstances could not be as- [442] sured by Japanese strength alone. Therefore, the northern route was selected.

By routing the striking force to pass between Midway and the Aleutians, it was expected to pass outside the patrol zones of United States patrol planes. Moreover, screening destroyers were sent ahead of the fleet, and in the event any vessels were encountered the main body of the force would make a severe change of course and endeavor to avoid detection. If the striking force had been detected prior to X-2-day, it was planned to have the force return without executing the air attack. In the event of being discovered on X-1-day, the question of whether to make an attack or to return would have been decided in accordance with the local conditions. If the attack had failed, it was planned to send the main force in the Island Sea out to the Pacific in order to bring in the task force.

I would like to remark again, that this is Japanese phraseology and may appear a little strange in its reasoning processes.

Returning now to the prepared script, item 7 is entitled "Sources of data used in planning the Pearl Harbor attack were as follows." These sources-I am speaking now from the point of view of the Japanese-were:

[443] (A) American public broadcasts from Hawaii.

(B) Reports of Japanese naval attachés in Washington, D. C. (C) Reconnaissance submarines in Hawaiian waters prior to the attack. A Japanese pilot states that at no time were visual land signals used from Hawaii.

(D) Information obtained from ships which had called at Hawaiian ports in mid-November.

Those are the only four sources which the Japanese have admitted. We know, however, that there is a fifth source:

(E) Espionage network in Hawaiian Islands, being uncensored cable communications with Japan.

That last is from an American source, not from the Japanese source. Mr. KEEFE. Under (C), with respect to signals, I didn't quite catch that. It doesn't appear here.

Admiral INGLIS. I beg your pardon. I am glad you brought that up. That last sentence "a Japanese pilot states" came from this last source which we just received last night. That was a change in the script. Mr. KEEFE. That will be included in the mimeographed corrected statement which we will receive later?

Admiral INGLIS. That is right.

The VICE CHAIRMAN. And that goes under what? [444] Admiral INGLIS. Under source (C).

Now, again I must deviate from the original script and quote this last document which was just received yesterday.

A Japanese officer pilot has reported his belief "that information concerning all movements of ships into and out of Pearl Harbor was transmitted to the fleet through coded messages broadcast over a Honolulu commercial broadcasting station." Source was certain "that there was a Hawaiian Nisei"--a secondgeneration American of Japanese descent-"who was a Japanese naval officer, aboard the flagship Akagi, whose specific job was listening to these broadcasts and decoding them." Source said "that in his opinion the codes were many and varied but that if, for example, it was broadcast the German attaché lost one dog, it might mean that a carrier left Pearl Harbor. If the German attaché wanted a cook or houseboy, it might mean that a battleship or cruiser had entered the harbor."

Source states "that the information was conveyed on radio programs just following the news broadcasts, which he stated were at 6:30 a. m., 12 noon, and 7 p. m. He was prone to think that time following the 7 p. m., broadcast was

used since the Japanese agents would then have had an opportunity to convey information concerning a whole day's activities.

[445] I would like to say at this time that the endorsement which the authorities at Hawaii, the FBI, ONI, and MIS, have placed on this last document indicates that they cannot find any substantiation for this plan to use Honolulu commercial broadcasting stations to convey information to the Japanese task force. They also pointed out that this procedure would not have been necessary since the Japanese consul, who was the center of the espionage network, had full access to a direct connection via cable uncensored directly from Honolulu to Tokyo.

That completes the deviation from the original script, and I return now to item 8, which is "Details of execution."

[446] VIII. Details of execution: Study of the Japanese plan of operation indicates the Japanese high command made the following assumptions with regard to the United States Fleet:

(a) That the main body of the United States Pacific Fleet would be at anchor within Pearl Harbor on December 7, 1941, Sunday, Hawaii time.

(b) That a carrier force could be moved from home waters across the Pacific to within striking distance of the main islands of the Hawaiian group without undue risk of detection by Americar defensive reconnaissance.

(c) That should assumptions (a) or (b) 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. The other task forces of the Japanese Fleet (southern force, northern force, and the south seas force) would be available for this purpose. Implied in the plan is the assumption that, in the event of such an engagement, the combined strength of the bulk of available Japanese major fleet units would be sufficient to defeat the American Fleet.

(d) A powerful carrier air strike directed against the American forces based in Hawaii could, if tactical surprise were effected, achieve the strategic result of crippling the American Fleet; that such a strike would achieve also the [447] destruction of American land-based air power and thus permit the Japanese striking force to withdraw without damage.

The omission from the Japanese plans of provision for landings on Oahu was decided upon during discussions held on September 6 and 7 when operation order No. 1 was being put together. It was decided that no landing operation should be included because it would have been impossible to make preparations for such a landing in less than a month after the opening of hostilities; it was further recognized that the problems of speed and of supplies for an accompanying convoy would have made it unlikely that the initial attack could be ac-. complished without detection; it was further recognized that insuperable logistic problems rendered landings on the island impractical.

The complete plan of the Pearl Harbor attack was known in advance to members of the Navy General Staff, the commanders in chief and Chiefs of Staff, and staff members of the combined fleet headquarters and first air fleet headquarters. Part of the plan was known in advance to the Navy Minister, Navy Vice Minister, and other ranking naval officers.