Much more consequential was the assessment that the
Zuikaku
, too, would have to be withheld from the coming operation. Though entirely undamaged, she had lost so many of her planes and pilots that she was deemed not battleworthy. The historians Jonathan Parshall and Anthony Tully have conducted a careful analysis of the number of airplanes that were available to the
Zuikaku
. She came into port at Kure with all of the planes—from both carriers—that had survived the battle. Relatively few were fully operational attack planes—merely nine bombers and six torpedo planes—through there were twenty-four Zero fighters. In addition, however, there were eight bombers, four torpedo planes, and one more fighter that were only lightly damaged and could have been repaired in time to take part in Operation MI. That would have given the
Zuikaku
a total of fifty-six airplanes, which was only seven short of her normal complement.
An alternative would have been to assign air squadrons from other carriers to the
Zuikaku
, though that violated not only Japanese doctrine but also their sense of propriety. It would be like sending eight baseball players out on the field, dressed in mismatched uniforms. Parshall and Tully conclude that
“Zuikaku
could have been made available if her presence had been considered vital.” But it was not, and that reflected Japanese overconfidence as well as their assumption that the Americans had lost two carriers in the Coral Sea, so that as a result the superiority of the Kid
ō
Butai over the Americans had actually been increased even without CarDiv5.
12
There was another consequence of the Battle of the Coral Sea that should have given the Japanese, and Yamamoto in particular, pause. Although the Americans had failed to sink either of the big Japanese carriers, their dive-bomber pilots had put three 1,000-pound bombs onto the flight deck of the
Sh
ō
kaku
—the newest and fastest of Japan’s carriers. This alone should have diminished the smugness within the Combined Fleet staff that the Kid
ō
Butai was so vastly superior to its opponent that the outcome of a confrontation was a foregone conclusion—that all it would take to eliminate the American carriers was “one touch of the armored gauntlet.”
13
In Hawaii, Rochefort’s operatives in Hypo had followed events in the Coral Sea with intense interest, but they continued to monitor other radio traffic
as well. On May 7 (the day American pilots sank the
Sh
ō
h
ō
), they intercepted a message that revealed Japanese plans to hold an “aviation conference” in which all four carriers of CarDiv 1 and 2 would participate. The next day (the day the
Lexington
went down), another message associated those four carriers with two battleships of BatDiv 3 and the cruisers of CruDiv 8. On May 10, Layton briefed Nimitz that “forces in Jap waters involving 1 or 2 CarDivs, a BatDiv, and Light Forces are preparing for operations” that were likely to begin on or about the end of May.
14
Rochefort was convinced that the target of this new offensive was Midway. The formation of a new enemy fleet, the dramatic increase in radio traffic, and the buildup of forces in Saipan all pointed to an offensive in the central Pacific. The clincher was the frequent use of the geographic designator “AF” in the message traffic. Anyone at all involved in traffic analysis knew that in the Japanese two-letter geographical designator system, “A” stood for an American possession (Hawaii, for example, was “AH”). Moreover, it was clear that “AF” had an airfield and that it was near Hawaii. In March, a Japanese seaplane reporting weather conditions near Midway had reported back to its base that it was passing AF. To Rochefort there was no other possible conclusion: AF meant Midway. In May, a circulated list of “known area designators” included AF as Midway. Rochefort’s number two man, Lieutenant Thomas H. Dyer, recalled that “there was little doubt in the minds of FRUPAC [HYPO] that AF was Midway.”
15
In Washington, however, doubts remained that Midway could be the target. Redman in OP-20-G continued to suspect Rochefort’s analysis; he worried that the Japanese might be preparing another attack on Port Moresby, or, even more worrisome, an assault on New Caledonia or Fiji. Long-range Japanese plans did indeed include an attack on Fiji and New Caledonia, but only after the capture of Midway. Rochefort found Redmond’s suggestions wrongheaded and annoying. Even a quarter of century later, the memory of it still angered him. “There was no other line of reason,” he insisted in a 1969 interview, “just none at all.” He knew that Redman had little expertise in code breaking and attributed his skepticism to the not-invented-here syndrome. In an obvious reference to Redman, Rochefort recalled, “We were quite impatient that people could not accept our reasoning.”
16
On May 15, Layton’s morning brief to Nimitz concluded that “there can no longer be any doubt that the enemy is preparing for an offensive against U.S. Territory. It is known that an attempt will be made to occupy MIDWAY and points in the ALEUTIANS.” That same afternoon, however, Nimitz received a message from King in which the CominCh and CNO declared it was “probable” that the next enemy thrust would be aimed at “Northeast Australia, or New Caledonia and Fiji,” and in which King suggested that the apparent interest in Midway was intended “to divert our forces away from SoPac.” He even suggested that the planes and air crews from the lost
Lexington
and the crippled
Yorktown
should be sent to airfields in Australia and Hawaii as a defensive force.
17
Nimitz found King’s advice less than helpful. A week before, perhaps in response to Nimitz’s transfer of air units to Midway, King had sent him a note reminding him that theater commanders were not authorized to “permanently transfer units” within their command area “without authority from War or Navy Department.” At the bottom of that message, Nimitz had scrawled: “In spite of unity of command.” It was as close as he came to open rebellion. Now, in response to King’s latest suggestion that Midway might be a mere diversion, Nimitz was tactful. “There may well be three separate and possibly simultaneous enemy offensives,” he wrote back, but they included “a major landing attack against Midway for which it is believed the enemy’s main striking force will be employed.” Since he lacked sufficient strength to oppose all three operations at once, Nimitz thought it logical to deploy the available American carrier assets to defend the most important of them—at Midway. Moreover, he preferred to keep the
Yorktown
operational and use the orphaned squadrons from the
Lexington
and
Saratoga
to fill out her complement of planes and pilots. Nimitz was willing to push back against King because he was confident that Rochefort and Layton knew what they were talking about. The Running Summary at CinCPac headquarters for May 16 read, in part, “Unless the enemy is using radio deception on a grand scale, we have a fairly good idea of his intentions.”
18
King capitulated, writing Nimitz, “I generally agree with you.” Even now, however, he urged Nimitz to keep an eye on New Caledonia and Fiji and to be prepared to shift forces there if necessary. Though Nimitz did
not expect it would be necessary, he promised that he would do so. “Will watch situation carefully,” he pledged, “and return Halsey to Southwest if imminent concentration is indicated.” He ordered Halsey to return at once to Pearl Harbor and to avoid being sighted by the enemy as he did so—his sense of urgency reflected in a follow-up message to Halsey to “expedite” his return. As King had anticipated, the removal of U.S. carriers from the southwest Pacific had implications for the Anglo-American alliance. When an alarmed British first sea lord queried King about why the carriers were being withdrawn, King risked a security breach by telling him that the “imminence of enemy attacks on Midway and Alaska” made it necessary.
19
King had come around to the belief that Midway was the enemy target. Nonetheless, given the size and strength of the Japanese offensive, he advised Nimitz to be responsibly cautious in responding to it. “Our appropriate strategy,” he wrote to Nimitz, “is to … employ strong attrition tactics, and not repeat
not
allow our forces to accept such decisive action as would be likely to incur heavy losses in our carriers and Cruisers.” He even proposed sending the
Yorktown
back to Bremerton for repairs “in order to avoid exposure to attack.”
20
But “decisive action” was exactly what Nimitz had in mind. He expected Halsey to reach Pearl on about May 25; the
Yorktown
was to arrive three days later. If
Yorktown
could be patched up in less than four days, he planned to send her out again, to join Halsey’s two carriers in a battle with the Kid
ō
Butai. He had been willing to pit two American carriers against three or four enemy carriers in the Coral Sea. Now he was willing to send out two or three American carriers against four Japanese flattops. For all his cool manner and calm demeanor, Nimitz was eager to confront the Japanese. Unlike Yamamoto, he was no gambler, nor did he ignore inconvenient facts. His was the calculating mind of a man who reviewed all the available information, weighed the odds carefully, and planned accordingly.
21
As he saw it, three American carriers, plus the airstrip on Midway Island, gave him four airplane platforms—the same as the Japanese; and if the airfield on Eastern Island at Midway could not maneuver, neither could it be sunk. Indeed, Nimitz greatly increased the number of planes on Midway. By the end of the month, it would house well over one hundred planes—patrol
planes, scout bombers, torpedo planes, Marine fighters, and twenty-three U.S. Army bombers, including nineteen B-17 Flying Fortresses—more planes than on any carrier. To be sure, many of them were not frontline combat units, and few of their pilots had been trained in antiship tactics. Nonetheless, at the very least Midway seemed able to defend itself and would likely contribute to the attack on the Japanese carriers.
22
Finally, and decisively, the Americans knew what was coming, where it was coming from, and more or less when it was coming. Nimitz believed he held a strong hand. He expected to win.
Though King now accepted that Midway was the object of the Japanese movement, Nimitz still encountered resistance from Washington, and in particular from Redman in OP-20-G and Richmond Kelly Turner, the head of the War Plans Division, both of whom continued to worry that the real Japanese target might be New Caledonia or Fiji. Rochefort was annoyed by this, and was tempted to tell them so. Instead, he sought to find a way to convince the skeptics, telling Jasper Holmes that they needed to do something that would “prove to the world that AF is Midway.” Holmes, whose background was in engineering, immediately thought of the large salt-water evaporators that supplied fresh drinking water to the Midway garrison. This led to a gambit that has subsequently become famous in the lore surrounding the Battle of Midway. On May 19, Rochefort asked that a message be delivered to Midway by submarine cable, ordering them to send a radio message to Pearl Harbor—in the clear—stating that their salt-water evaporator had broken down and that they were running short of fresh water. Sure enough, two days after this bogus report hit the airwaves, an intercepted Japanese message reported that “AF” was short of drinking water.
*
Rochefort did not wave this evidence in the face of the skeptics. In fact, he did not even report the message when it came in, allowing the stations in Melbourne and Washington to discover and report it on their own.
23
Nimitz scheduled a staff meeting for the morning of May 25 to make final plans. Halsey’s Task Force 16 was due in that day, and Nimitz needed to be sure that everyone understood the timetable for the turnaround and redeployment. Nimitz invited Army General Delos C. Emmons, commander of the Hawaiian Department, and General Robert C. Richardson, a personal friend of General George C. Marshall, who represented the War Department. Nimitz wanted them to hear the latest intelligence report from Rochefort himself. It was the first time Rochefort had been invited to brief the high brass personally. The admiral and generals assembled at the appointed hour, but Rochefort was not there.