They were more interested in the battleships. From The Japanese Navy in World War II (p. 53). Naval Institute Press. Kindle Edition.
Author Mitsuo Fuchida.
Issued 2200, 6 December; received 1036, 7 December
Activities in Pearl Harbor on the morning of 5 December:
Arrived: Oklahoma and Nevada (having been out for eight days)
Departed: Lexington and five heavy cruisers Ships in harbor as of 1800, 5 December: 8 BB, 3 CL, 16 DD In docks: 4 CL (Honolulu class), 5 DD
Issued 1700, 7 December; received 1900, 7 December
No balloons, no torpedo-defense nets deployed around battleships. No indications observed from enemy radio activity that ocean patrol flights are being made in Hawaiian area. Lexington left harbor yesterday (5 December, local time) and recovered planes. Enterprise is also thought to be operating at sea with her planes on board.
Issued 1800, 7 December; received 2050, 7 December
Utah and a seaplane tender entered harbor in the evening of 5 December. (They had left harbor on 4 December.) Ships in harbor as of 6 December: 9 BB, 3 CL, 3 seaplane tenders, 17 DD In docks: 4 CL, 3 DD All carriers and heavy cruisers are at sea. No special reports on the fleet. Oahu is quiet and Imperial General Staff is fully convinced of success. These reports had presumably been sent from Honolulu, but I do not know the details.
On 6 December, after fueling the Second Carrier Division and the Screening Force, the Second Tanker Train broke off from the task force. On the next day the First Tanker Train fueled the screen again and departed. Our force then increased speed to twenty-four knots and raced toward Pearl Harbor. On the carrier decks planes were lined up wing to wing for their final check. Maintenance crews and flying crews worked assiduously to complete final preparation of their planes.
About this time we received Admiral Yamamoto’s message for going to war: “The rise or fall of the empire depends upon this battle; everyone will do his duty with utmost efforts.” The message was immediately relayed to all hands, and the “Z” flag was hoisted on the Akagi’s mast. This was the same signal flag that had been run up on the Mikasa almost thirty years before in the Straits of Tsushima.
At 1225 on 7 December (1725, 6 December in Honolulu) a message came in from the submarine I-72: “American fleet is not in Lahaina anchorage.”
This anchorage was used for training because it was open and deep. If the Pacific Fleet had been there, we would have had our best chance for success, and we had hoped accordingly. Receipt of the negative information, however, blasted our hopes for such an opportunity.
It was now obvious that the warships were either in Pearl Harbor or at sea. Admiral Nagumo was thumbing through the message log to check on battleships reported to be in Pearl Harbor. Completing the count, he looked up and said to the staff members, “All of their battleships are now in. Will any of them leave today?”
The intelligence officer, Lieutenant Commander Ono, was the first to reply: “Five of their eight battleships reached port on the twenty-ninth, and two others left that day, returning on the sixth. There is one more that has remained in harbor all this time, supposedly under repair, or perhaps in dry dock. The five ships that arrived on the twenty-ninth have been there eight days, and it is time for them to leave. I suspect they may go out today.”
“Today is Saturday, 6 December,” said Chief of Staff Kusaka. “Their general practice is to leave on Tuesday, which would be the ninth.”
“It is most regrettable,” said Genda, the operations officer, “that no carriers are in.”
“On 29 November,” Ono explained, “the Enterprise left harbor accompanied by two battleships, two heavy cruisers, and twelve destroyers. The two battleships returned on the sixth, but the rest have not yet come back. The Lexington came in on the twenty-ninth and left with five heavy cruisers on the sixth. Thus, the Enterprise ought to return today. The Saratoga is under repair at San Diego, and the Wasp is in the Atlantic. But the Yorktown and the Hornet belonging to the Pacific Fleet must be out here. They may have arrived with the Enterprise today.”
“If that happens,” said Genda, “I don’t care if all eight of the battleships are away.” “As an airman,” remarked Oishi, “you naturally place much importance on carriers. Of course it would be good if we could get three of them, but I think it would be better if we get all eight of the battleships.”
Then Chief of Staff Kusaka, who had always been strong on statistical studies of the U.S. Pacific Fleet, spoke: “There is only a slight chance that carriers may enter the harbor on Saturday, and it seems unlikely that the battleships would leave on Saturday or Sunday. We may take it for granted that all eight battleships will be in the harbor tomorrow. We can’t do anything about carriers that are not there. I think we should attack Pearl Harbor tomorrow.”
Thus he set the stage for the decision of the task force commander, which was made known on the evening of 7 December, when Admiral Nagumo gave his appraisal of the enemy situation:
1) Enemy strength in the Hawaiian area consists of eight battleships, two carriers, and about ten heavy and six light cruisers. The carriers and heavy cruisers seem to be at sea, but the others are in the harbor. Those operating at sea are most likely in the training area south of Maui; they are not in Lahaina.
2) Unless an unforeseen situation develops tonight, our attack will be launched upon Pearl Harbor.
3) So far there is no indication that the enemy has been alerted, but that is no reason to relax our security.
