Pearl Harbor Betrayed (31 page)

It was the last time that Genda and Fuchida had the air crews of all the carriers together, and they made the most of it. Neither wanted to dampen the enthusiasm of the pilots, but Fuchida had to acknowledge to them the possibility that the American fleet would not be in the harbor and could not be found. In that disappointing event, Fuchida told interrogators after the war, “we would have scouted an area of about 300 miles around Oahu and were prepared to attack. If the American fleet could not be located, we were to withdraw.” (Interestingly, no mention was made of attacks instead on land installations such as repair facilities and the fuel farms.) The carriers would take up station about fifty miles south of Oahu, recover their scouting aircraft, and retire to the Marshalls to await further instructions.
43

There were many such imponderables facing Nagumo, Genda, and Fuchida, not in any particular order: Suppose the American defenders had distant aerial reconnaissance under way in the sector north of Oahu—agents associated with the consulate in Honolulu had not reported any—where Nagumo's carriers would make much of their final dash toward launch position in full daylight, and suppose the skies overhead were clear, what then? Suppose American naval intelligence had divined the Japanese intention and, even now, was preparing to ambush the
Kido Butai
(as U.S. Navy carriers, acting on superb intelligence, would trap the Japanese in the Battle of Midway [4–6 June 1942], when Nagumo again was task force commander). Suppose fog socked in the carriers on X-Day, foreclosing the possibility of recovering aircraft, thus causing Japanese air losses to be higher than those of the Americans? Suppose the negotiators in Washington reached an accord, and the Hawaii expedition was recalled, and the Americans then reneged: could a surprise operation be remounted weeks or months later when thousands of sea and air crewmen were privy to the secret?

*   *   *

Following last-minute preparation of the ships for battle, which included the rigging of rolled mattresses (mantelets) around the exterior of bridge and island structures to protect against bomb splinters, Nagumo's formidable armada weighed anchor and sortied into the North Pacific. The time was 0600 on 26 November (Japan time). Chief Ordnance Officer Sadao Chigusa, on board the destroyer
Akigumo,
wrote in his diary, “0600. At last we left Hitokappu Bay for Hawaii to attack Pearl Harbor, seeing M[oun]t Berumarube disappear behind us.… A northwest wind of 5–6 m/second (10–12 knots) blew, and it was very cold with occasional gusts of driving snow.… The sally of our great fleet was really a majestic sight.”
44
Kido Butai
steamed east at a steady 12 to 14 knots, the carriers in parallel columns of three, with the tankers trailing. The two battleships and two heavy cruisers flanked the carriers. The light cruiser and the destroyers formed the perimeter, or screen. The three submarines advanced at twenty-three knots to take up scouting stations 200 miles ahead.

The course chosen, 095 degrees, would take the fleet through the “Vacant Sea,” which was practically devoid of commercial shipping, between the southern routes that lay between Hawaii and the ports of China and the northern great circle routes that lead near the Aleutians. Two other courses had been considered. One, a central route, would have taken the fleet directly toward the Hawaiian archipelago; the other, a southern route, would have passed the fleet through the Marshall Islands to the southwest of Hawaii. Both had the advantage of providing calm seas for refueling, as against conditions in the Vacant Sea, which normally offered twenty-four days of storm for every seven days of calm. But both posed dangers of encountering commercial vessels en route and of being sighted by U.S. Navy patrol flights out of Wake, Midway, Palmyra, and Johnston Islands. The refueling problem presented by gale winds and heavy seas on the northern route could be overcome, it was decided, by training. Too, the very improbability of a punishing North Pacific crossing assisted in the deception plan. Maintaining surprise was the overriding key to a successful operation. Hence the 095 degree heading, on which, to its own surprise, the fleet found fair seas during its first six days. The choice of Sunday, 7 December (Hawaii time) for the attack was owed primarily to the fact that, as the Honolulu consulate had reported, the U.S. Pacific Fleet followed the habit of entering harbor on Friday or Saturday after exercises and of departing on Monday or Tuesday. Also the Sunday date coordinated well with attacks scheduled in the Southern Operation.

The first refueling at sea of four of the carriers and the cruisers took place five days out. We know that the carrier
Kaga
took an oiler in tow, distance apart seventy to eighty meters, using a manila hauser about six inches in diameter; after the tow was passed, and speed of the vessels was reduced to eight knots, fuel was passed through a hose about eight inches in diameter, rubber outside, metal inside, supported by a two-inch wire jackstay. Fuel intakes were fitted on both quarters of
Kaga
. Oiling took about six hours. Carriers
Soryu
and
Hiryu,
though the fastest of the carriers, had the lowest fuel capacities (4,000 metric tons), hence they had to be replenished daily. Fuel tanks on the short-legged destroyers had to be topped off every other day. From the diary kept by her ordnance officer, we learn that the newly commissioned destroyer
Akigumo,
replenished whenever the opportunity presented itself, day or night, with the donor tanker either alongside or astern.
45
Visibility was usually so bad when the tankers approached the warships that towing spars for position-keeping were almost constantly in use.

Meanwhile, all ships posted lookouts as a guard against possible U.S. air interdiction.
Kaga,
for example, had twenty-one sure-eyed men on two-hour tricks manning seven AA machine-gun positions around the clock. But no enemy aircraft would be sighted during the voyage; nor would any warships. Encountering U.S. flag merchant shipping was no problem, since on the day after the 16 October war warning OpNav had ordered all merchant transpacific traffic diverted to a southern route that ran well clear of the Japanese mandates, south through the Solomon Islands, then west of the Santa Cruz Islands, then through the Torres Straits between Australia and New Guinea, “taking maximum advantage of Dutch and Australian patrolled areas.”
46
Nagumo may have learned of this course alteration from Japanese intelligence.

In ships' radio shacks operators listened for the latest encrypted intelligence on Pearl Harbor. It came from consular agents in Honolulu, relayed to
Kido Butai
through the Imperial General Staff, with unexplained delays of three to five days. Thus, the report “Activities in Pearl Harbor as of 0800/28 November [Hawaii time]” reached the ships on 2 December [Japan time]. It read:

Departed: 2 battleships (
Oklahoma
and
Nevada),
one carrier (
Enterprise
), 2 heavy cruisers, 12 destroyers. [This was Halsey's Task Force 8 ferrying Marine F4Fs to Wake. He in fact took nine destroyers.]

Arrived: 5 battleships, 3 heavy cruisers, 3 light cruisers, 12 destroyers, 1 tanker.

Ships making port today are those which departed 22 November.

Ships in port on afternoon of 28 November estimated as follows:

6 battleships (2
Maryland
class, 2
California
class, 2
Pennsylvania
class).

1 carrier (
Lexington
).

9 heavy cruisers (5
San Francisco
class, 3
Chicago
class, and
Salt Lake City
).

5 light cruisers (4
Honolulu
class and
Omaha
).
47

Operators listened, too, for special code phrases, the meanings of which would be known to cryptographers on board the flagship
Akagi,
phrases such as “the fate of the Empire,” “the cherry blossoms are all in their glory,” and the one for which Nagumo anxiously awaited:

THIS DISPATCH IS TOP SECRET. THIS ORDER IS EFFECTIVE 1730 ON 2 DECEMBER COMBINED FLEET SERIAL 10. CLIMB NIITAKAYAMA 1208 REPEAT 1208
48

Niitakayama was the highest mountain in Japanese-occupied Korea. The code phrase was the order to “Proceed with attack.” The 1208 (8 December Japan time) was the date for the attack.

The signal crackled through
Akagi
's earphones on 2 December.

There had been no diplomatic breakthough in Washington. The operation was go.

Shortly after receipt of the order, Nagumo's Striking Force crossed the 180th meridian into the Western Hemisphere.

*   *   *

Among the critical predicates of success in the Hawaii Operation, joining the ability to refuel ships in the rough North Pacific seas and avoidance of premature discovery by the enemy, was the availability of continuous intelligence about the presence of principal U.S. fleet warships in Pearl Harbor. That information was supplied on an almost daily basis through the Japanese consulate in Honolulu by a trained naval intelligence agent named Yoshikawa Takeo. Arriving by ship at Honolulu on 27 March 1941 under the cover of a junior diplomat named “Tadashi Morimura,” the twenty-nine-year-old, English-speaking Yoshikawa took up ostensible duties as chancellor of the consulate. He was rarely in his office, however, with the full blessing of the also newly arrived consul general, Kita Nagao, and his vice consul, Okuda Otojiro, who both knew of and fully supported his mission, which was to reconnoiter all U.S. Army and Navy bases and airfields on Oahu, with special emphasis on Pearl Harbor, where he was to observe and report regularly on ship movements.

Yoshikawa was not the first to undertake this work. The consular treasurer, Seki Kohichi, who had briefly attended Japan's naval academy at Eta Jima, made regular observations at Pearl Harbor, seven miles distant from the consulate, in 1940 and in the first months of 1941. But Yoshikawa, a graduate of Eta Jima, was the first agent in Honolulu with a professional espionage background. On paper he had a thorough knowledge of the U.S. fleet, and, soon, with the help of a Navy-wise taxi driver named John Yoshige Mikami and a young dual citizenship–holding Nisei with a 1937 Ford named Richard Masayuki Kotoshirodo, Yoshikawa was making regular observations of ship movements in and out of Pearl. The ships were easily observable from various highway and street sites, from Aiea Heights, from Kamehameha Highway, between Aiea and Makalapa, from a pier at Pearl City, northwest of the harbor, and from a telescope-equipped teahouse on Alewa Heights that overlooked both the harbor and Hickam Field. Driving with Mikami along the Kokokahi Road on the east coast of Oahu, he also studied the Kaneohe Naval Air Station, home of the patrol bomber (PBY) wing. Twice he and Mikami drove by the Army's Schofield Barracks, and once, in autumn, he took a geisha friend on a tourist airplane flight over southern Oahu that provided excellent views of Pearl and Hickam as well as of the airfields at Wheeler and Ewa. Everything he saw—ships, airstrips, aircraft, hangars—he reported regularly and in detail to Tokyo, utilizing the consulate code room and radio facilities.
49
It was his information, for example, that produced the ship movements signal that reached
Akagi
on 2 December.

On 24 September, Foreign Minister Togo, acting on the request of the Naval Staff's Third Bureau (Intelligence), directed the Honolulu consulate to generate a second series of reports, these to focus not on ship movements but on berths and anchorages of major warships
in port.
The “strictly secret” Message No. 83 read:

1. The waters [of Pearl Harbor] are to be divided roughly into five sub areas. (We have no objection to your abbreviating as much as you like.)
   Area A. Waters between Ford Island and the arsenal [navy yard].
   Area B. Waters adjacent to the island south and west of Ford Island. (This area is on the opposite side of the island from Area A.)
   Area C. East Loch.
   Area D. Middle Loch.
   Area E. West Loch and the communicating water routes.

2. With regard to the warships and aircraft carriers, we would like to have you report on those at anchor (these are not so important), tied up at wharves, buoys, and docks. (Designate types and classes briefly. If possible we should like to have you make mention of the fact when there are two or more vessels alongside at the same wharf.)
50

After consulting with Yoshikawa, Consul General Kita responded to No. 83 on the twenty-ninth. His message proposed an even more precise reporting system utilizing code designators:

1. Repair dock in the Navy Yard (the repair base referred to in my message to Washington #48): KS.

2. Navy dock in the Navy Yard (Ten Ten Pier): KT.

3. Moorings in the vicinity of Ford Island: FV.

4. Alongside at Ford Island: FG (east and west sides will be designated A and B respectively).

On 18 November another area, N, was added to the grid.
51

The effect of these five designators was to place what has been called an “invisible grid” over Pearl Harbor. Togo's and Kita's messages, which were sent in a low-grade consular cipher known as J-19 (but also under the umbrella of Magic), were intercepted by U.S. Navy operators in Station Hypo at Pearl Harbor, named after the “H” of Heeia on the east side of Oahu where the Pacific Fleet's radio intercept towers were located. But Commander Rochefort, chief of the Combat Intelligence Unit of the Fourteenth Naval District, was under orders from Main Navy to send all consular intercepts, unread, by Clipper pouch to Washington, for decryption and evaluation there. This meant, said Kimmel's intelligence officer Layton, that “the Pacific Fleet, the principal instrument of our military power in the Pacific, was not equipped to monitor the enemy beyond its harbor wall.”
52
In Washington, where consular traffic was given a low priority, Togo's message of 24 September was not decrypted (by the Army) until 9 October; and Kita's scheme was not read (by the Navy) until the following day. Colonel Rufus C. Bratton, chief of the Far Eastern Section in Army G-2, routed Togo's message to Stimson, Marshall, and Gerow, chief of War Plans, but none found it of special interest, much less alarming. On the Navy side, Lt. Comdr. Alwin D. Kramer, of ONI's Translation Section, Communications Division (OP-20-GZ), routed Togo's and Kita's messages through his own hierarchy of Knox, Stark, and Turner, eliciting the same indifference.