10

 

Turnaround in the Pacific War

 

 

For the six months following Pearl Harbor, the Japanese war machine was invincible. The U.S. islands of Guam and Wake fell within days after the Pearl Harbor raid. In the Philippines the Japanese sliced up the American and Filipino armies, forcing the Americans to retreat into the hopeless corners of Bataan and Corregidor and, in May 1942, to surrender. On the China coast, the American garrisons at Shanghai and Tianjin were seized. British-led forces were pushed out of Burma and Malaya. The Dutch East Indies yielded up their riches not only in oil but also in rubber, rice, timber and metals. The strategic stronghold at Rabaul in New Britain fell. The Japanese extended their Greater East Asia Coprosperity Sphere to include the whole arc of the central, south and southwest Pacific and were threatening the supply lines between the U.S. and Australia.

During those first months of 1942, the leadership that would direct the U.S. war effort in the Pacific had established itself. In Hawaii, Admiral Chester W. Nimitz had become the new commander of the Pacific Fleet. General MacArthur had been ordered to leave his besieged troops on Corregidor and escape to Australia in a torpedo boat. Moreover, the two commanders' cryptologic support teams were firmly in place. On Oahu, Edwin Layton, the fleet's chief intelligence officer, and Joe Rochefort were relieved to find that Nimitz refused to consider any shortcomings in their Pearl Harbor performance and wanted them to continue serving him. MacArthur had seen to it that his Cast cryptographers were spirited away to Australia on submarines before he himself left the Philippines, vowing, "I shall return."

In terms of cryptology, the explosive geographic expansion by the Japanese had one consequence that was to bring a decisive reversal in the course of the war. Japanese intelligence leaders knew that the security of their systems depended on regular replacement of the codebooks that were the basis of their nonmachine codes. They had planned to change their workaday naval code, JN-25, on April 1, 1942, but the distribution of their codebooks was made impossible by the twenty-million-square-mile spread of Japanese commands and the growing profusion of recipients. The date for the changeover was pushed back to May 1, then to the beginning of June. The delays gave Allied cryptanalysts those extra months to master JN-25.

In the windowless basement of the Fourteenth Naval District's Administration Building, known as "the dungeon," Joe Rochefort was on hand virtually nonstop. He paced around with a red smoking jacket over his uniform, both to keep him warm in the dank quarters and to provide the deep pockets he needed for his pipe, tobacco pouch and copies of messages of special interest. His work uniform was completed with house slippers because the concrete floors hurt his feet. In addition to overseeing the direction-finding, intercept, and traffic analysis operations along with cryptanalysis, Rochefort had to manage the influx and training of new recruits now flooding into his cellar headquarters.

Of these newcomers the most bizarre was a contingent of musicians left jobless by the severe damage to their ship, the USS California, in the Japanese attack. To the amazement of Rochefort and Dyer, the band provided capable and even some exceptional additions to the team.

The new, closer cooperation between the Allied cryptographic units in the Pacific and in Washington quickly began to produce results. Gone were the cumbrous communications methods of the pre-Pearl Harbor days. Now the cryptanalytic units flashed new discoveries to each other via radio-teletypewriter links. Soon the analysts were solving some forty percent of JN-25's code groups, but since those were the most often used words and phrases, the meaning of a high percentage of entire messages could be determined, or at least guessed at.

In April the U.S. military, knowing how badly the American people needed a morale boost, planned what became known as "Doolittle's raid" on mainland Japan. Colonel James Doolittle would load sixteen B-25 bombers on the flight deck of the aircraft carrier USS Hornet, slip within five hundred miles of Japan, lead the bombers so they could drop bombs and incendiaries on Tokyo and other cities, and fly on to those parts of China still held by Chiang Kai-shek. To carry out this bold act, the Hornet was joined by Admiral William F. "Bull" Halsey on the aircraft carrier Enterprise and by several escort vessels. Fortunately, Halsey's crew included an experienced intelligence officer and intercept operators. When the task force was still well short of its five-hundred-mile goal, the intelligence team picked up Japanese radio traffic revealing that Halsey's ships had been sighted. Japanese leaders took almost two hours to overcome their shock and disbelief, but then their radio channels crackled with transmissions as they sought to organize a huge sea hunt. Halsey decided to launch the bombers sooner than planned but not so late that his precious carriers and other ships would be endangered. While the attacks themselves were mere pinpricks, the raid gave the U.S. the semblance of a reprisal for Pearl Harbor, a publicity bonanza and a lift to American spirits. FDR stirred imaginations by claiming the bombers were launched from Shangri-La, the mythical kingdom in James Hilton's novel Lost Horizon.

The Doolittle raid had a much more important consequence than that of its bombs. In those early days of 1942 the Japanese high command, flush with victory, was debating its next offensive strategies. One group wanted to parlay the capture of Rabaul into the seizure of Port Moresby, on the south coast of the huge island of New Guinea, which hangs over Australia in the north like a giant incubus. Port Moresby was only a short hop across the Coral Sea to the Australian mainland. The group also advocated conquests in the Solomon Islands and beyond to sever Australia's links with the U.S.

Admiral Yamamoto pressed for an alternative plan. He wanted to extend the Coprosperity Sphere in the other direction: to establish a new perimeter that included the Aleutian Islands in the north and Midway Island on the eastern sea frontier. He argued that his strategy would lead to eliminating U.S. power in the Pacific in two ways. The capture of Midway would provide a base for the conquest of Hawaii. And the need for the U.S. to defend the island would draw the battered Pacific Fleet into deep water where he could complete the decisive battle he had started at Pearl Harbor.

The Decisive Battle was an important concept to Japanese sea lords, as John Prados emphasized in his book Combined Fleet Decoded. "The Japanese fleet," he wrote, "was built to engage in the Decisive Battle, trained to conduct it, and officers and men were imbued with the idea of the Decisive Battle almost as a tradition, an ideology, a cult." The pervasive idea traced back to the Japanese victory over Russia in the 1904 battle at Tsushima. Russia had put together a fleet in European waters and then sent it halfway around the world to engage the Japanese. Because of the long journey and a variety of tribulations along the way, the Russians had arrived in the Far East thoroughly dispirited, and they were soundly defeated. Just so, Yamamoto believed, could Japan humble the U.S. Navy. In traversing the vast distances of the Pacific, the American fleet could be harried, weakened and confused by submarine torpedo attacks, destroyer flotillas and aircraft strikes. Then the concentrated power of the Imperial Navy could fall on it and deliver the deathblow.

The loss of Midway, the seizures in the Aleutians and the annihilation of the U.S. fleet, Yamamoto stressed, would dishearten the American people. The admiral again held out the prospect of a negotiated peace on terms dictated by Japan.

Doolittle's raid swept away any resistance to Yamamoto's plan. As he himself commented, "Even though there wasn't much damage, it's a disgrace that the skies over the Imperial Palace should have been defiled without a single enemy plane shot down." It must not happen again. Midway was near enough to serve as a launching site for similar attacks in the future, and the Dutch Harbor base in the western Aleutians was also too close for comfort. The army, which had heretofore refused to participate in the admiral's scheme, now insisted on becoming a part of it.

Japan's military leadership, basking in the knowledge that their losses had been far less than anticipated, decided it was unnecessary to choose between the alternatives. They could do both: carry out the drive against Port Moresby while also proceeding with the Midway-Aleutians campaign.

 

 

Winning the Battle of the Coral Sea

 

Rebuffing the Japanese commanders' first attempt to take Port Moresby was primarily the task of the U.S. Navy. Rochefort's team informed Admiral Nimitz of the great flotilla of Japanese warships that were escorting transports carrying a whole division of invasion troops, heading down from Rabaul. The Japanese objectives were to capture Tulagi, one of the Solomon Islands, and build an airfield there while also entering the Coral Sea to seize Port Moresby.

In his memoir, Layton emphasized that Nimitz's entire Coral Sea operation was guided by Rochefort's "sixth sense" in assembling seemingly unrelated information in partially decrypted enemy messages and turning the puzzle into an accurate picture of enemy intentions.

Believing his codebreakers, Nimitz evacuated the small Australian detachment at Tulagi before the Japanese invaders arrived. He also relied on advice from decodes to station his ships to the best advantage in the Coral Sea.

Vice Admiral Shigeyoshi Inouye, commanding the Japanese fleet, was expecting that his passage would prove a surprise to the Allies. His shock was great, therefore, when U.S. carrier-based planes began to attack and sink his ships.

The Battle of the Coral Sea, fought from May 4 to May 8, 1942, was a mix of poor judgment, faulty leadership, missed opportunities and lucky hits on both sides. Admiral Morison thought it might better be called "the Battle of Naval Errors," but he also wrote, "It was an indispensable preliminary to the great victory of Midway."

For the U.S., a prime opportunity was lost when one of Nimitz's commanders, Vice Admiral Jack Fletcher, became antagonistic toward the mobile intelligence unit aboard his flagship and turned a deaf ear to them. What had miffed him was that when he had asked the unit's leader to describe his work to a wardroom of officers, the leader's consciousness of his security restraints had caused him to refuse. Consequently, when the unit pinpointed the location of nearby Japanese carriers and revealed that they were in the vulnerable stage of refueling aircraft, Fletcher, still piqued, declined to act on the information.

In the end, the U.S. traded the sinking of a Japanese light carrier and heavy damage to another carrier for the loss of the Lexington and the crippling of the Yorktown. American fliers also downed a large number of enemy planes. Technically, in terms of ships sunk, it was a Japanese victory. But without carriers to provide air cover for the Port Moresby invaders, Yamamoto on May 18 called his ships and his occupation force back to Rabaul. Round one clearly went to the Allies.

Of larger significance, the Japanese for the first time in the war had suffered a setback. That realization gave the Allies' esprit a powerful boost.

 

 

Midway: "A Victory of Intelligence"

 

While Rochefort and his team were busy tracking the enemy's advance toward Australia from decrypted fragments, he also began detecting Ya-mamoto's Midway-Aleutians operation. Of special help was a decrypt of April 29 referring to the dispatch of maps of the Aleutian Islands. Another signal dealing with the "forthcoming campaign" used the words koryaku butai—"invasion force"—aimed at a destination encoded as AF. Rochefort and Layton informed Nimitz that something big was heading toward Hawaii.

In hindsight, it can be seen that Yamamoto's plans were flawed in the extreme. In setting the three objectives of taking the atoll, establishing control in the Aleutians and luring what was left of the U.S. Pacific Fleet out into the open sea, he was violating the principle of massing his strength. He thought of the Aleutian campaign as a useful feint, a clever deception, as well as a needed blunting of that northern scimitar hanging over the Japanese mainland. Instead it resulted in a ruinous division of his ships and carriers.

Cockiness made him sloppy. He allowed two other carriers to be left behind in home waters—one to be repaired after the Coral Sea battles, the other merely to receive a new complement of planes and pilots—when a determined effort could have added both to his fleet. In addition, when his huge force sailed toward Midway, he placed his four carriers forward in a close grouping that proved terribly convenient for U.S. attack planes. And instead of covering these all-important carriers with his battleships, he had the war vessels, including his flagship, Yamato, lag far behind, a floating headquarters remote from the action.

Most damaging of all was his attempt to use the same deceptive tactics at Midway that had worked for him at Pearl Harbor. Again he used fake radio traffic to create the illusion that his ships were in training operations near Japan. This time, thanks to the delay in introducing the new JN-25 code, Rochefort and his team were not to be fooled.

The intelligence supplied in the Coral Sea battles had confirmed for Nimitz that he could trust his codebreakers. When they began submitting evidence of a massive new Japanese thrust aimed at Midway, he sided with them against the view held by Washington analysts, as well as Washington chief Admiral Ernest J. King, that Rochefort was being duped. The Washington unit believed any move toward Midway was only a feint masking Yamamoto's real objective: the aircraft factories of Southern California. The U.S. Navy even dispatched a fleet, Admiral Morison has reminded us, to search for a Japanese carrier falsely reported to be descending on San Francisco.

Further, the Washington intelligence staff advised King that Halsey and his carriers should be kept in the Coral Sea, since the Yamamoto offensive might be directed there rather than toward Midway.

Rochefort was not subtle in disparaging these interpretations. Regarding an attack on the U.S. West Coast, he knew the Japanese lacked sufficient transports, tankers and food refrigeration ships to take on so remote an objective. Also, he judged it "ridiculous" and "stupid" to think they would strike so far east while the U.S. Navy ships at Pearl remained on their flank.

As for leaving carriers in the Coral Sea, MacArthur's codebreaking teams in Melbourne came to Rochefort's support. Their decrypts verified that the Japanese had abandoned amphibious operations against Port Moresby and were planning an overland offensive instead. Halsey's carriers could head for Pearl Harbor and Midway.

In his recorded oral reminiscences, Rochefort stated, "Possibly the best thing that ever happened to the Navy during the war was Nimitz's acceptance of Station Hypo's estimate of what the Japanese were going to do, not only at Coral Sea but at Midway and subsequent."

Even with Nimitz's approval, though, one big question remained. Where was "AF"? Rochefort had worked with the Imperial Navy's geographical bi-letter designations enough to know that AH was Hawaii and AK was Pearl Harbor. He was sure that references to AF in the intercepts stood for Midway, but none of the decodes made the identification certain. How could he make sure?

Lieutenant Commander Jasper Holmes knew that the Midway command depended on a plant that distilled seawater to supply the garrison's water needs. What if Midway sent out, both in plaintext and in a low-level code the Japanese were sure to read, that the desalinization plant had broken down and the island's supply of water was running desperately short? If AF was Midway, surely some mention of this crisis would show up in subsequent traffic.

The scheme was carried out, with the extra fillip of an answering plaintext transmission from Hawaii that a freshwater barge would be sent at once.

The deception worked. As Holmes reported, "The Japanese took the bait like hungry barracudas." AF's water troubles turned up in a decrypt, establishing beyond doubt that Midway was the target. Historian David M. Kennedy has called this resourceful stroke by Rochefort's team "the single most valuable intelligence contribution of the entire Pacific war." Its upstaging of the bigwigs in Washington, however, exacerbated their ill feelings toward Rochefort.

The ruse convinced Nimitz, who had already reinforced the defenses at Midway. He began preparing his David role against the Yamamoto Goliath, pitting twenty-seven surface warships against the enemy's eighty-eight. On May 25, Nimitz held a staff meeting that Rochefort had been ordered to attend. A punctual man, the admiral was annoyed when his chief cryptana-lyst showed up a half hour late. But when Nimitz saw what Rochefort had brought with him, all was quickly forgiven. Rochefort and his colleagues had spent the night decoding a long intercept. It revealed nothing less than the complete Japanese order of battle for the Midway attack. Plus, the intercept confirmed that the attack was scheduled not for mid-June, as Washington was claiming, but for June 3 or 4.

On May 28, the Japanese did switch to a new version of their JN-25 code, blacking out the Allied codebreakers for a time. But the changeover came too late. The Americans knew all they needed in order to take on the Japanese fleet.

Unlike the overconfident Yamamoto, Nimitz hastened to amass every element of naval strength he could muster. Although not an aviator himself, he understood the importance of naval air power. On the afternoon of May 27, the battered carrier Yorktown limped from the Coral Sea into Pearl Harbor. If it could be patched up in time, it would add a third carrier to Nimitz's fleet. Given the extent of its damage, the repairs could easily have consumed a couple of months, perhaps even a trip to the West Coast. Instead, crews swarmed over the vessel and on the morning of May 29 had it ready to put to sea, at least marginally battle worthy.

Nimitz received what seemed a serious setback to his plans when Bull Halsey arrived at Pearl with a skin disease that sent him to the hospital instead of aboard a flagship. Postmortems of the battle, though, suggest that in reality this was a felicitous change. The impulsive Halsey might not have fared as well in the complex operation as his cool, clear-thinking replacement.

This was Rear Admiral Raymond A. Spruance, who in his service under Halsey had shown himself to be an aggressive fighting man and a shrewd strategist. He would command one of Nimitz's task forces, with Jack Fletcher in charge of the other. Knowing from the Hypo codebreakers that the Aleutian operation was only a diversion, Nimitz sent northward a motley assortment of ships under Rear Admiral Robert A. Theobald.

On June 1, Yamamoto planned to place two picket lines of submarines between Pearl Harbor and Midway. The subs would be stationed there primarily to alert him if the U.S. fleet emerged in response to his surprise attack on the atoll. The operation was badly coordinated, and the subs were late in getting into position, but even if they had been on time they would not have detected the American ships; they had already passed the barrier.

For the previous month the defenses of the Midway atoll had been reinforced by inflows of antiboat and antiaircraft guns, two additional companies of GIs, five tanks, ten torpedo boats, stores of aircraft gasoline and a variety of planes that included B-17 Flying Fortresses. Midway was as ready as Nimitz could make it.

He proceeded to set his sea trap. His two task forces met at "Point Lucky," 325 miles northeast of Midway, a position that was expected to place them on Yamamoto's left flank. The three carriers would lie in wait, undetected, while long-range search planes from Midway sought out the Japanese fleet. Then every type of air power the U.S. could marshal, both from Midway and the carriers, would fall on the Japanese ships.

In Washington, suspicions still lingered that Nimitz and Rochefort were being gulled by a Japanese force that was only a decoy. Consequently, they were greatly relieved when on June 3 a flying boat from Midway spotted the invasion fleet almost exactly where Rochefort had predicted it would be. The Spruance and Fletcher task forces, along with the defenders at Midway, knew for certain what they must do.

At this point Yamamoto's plan began to show its flaws. His battleships, with their powerful eighteen-inch guns, could have pulverized Midway's defenses, but they were three hundred miles away. The softening up was left to Pearl Harbor's hero, Admiral Chuichi Nagumo, commanding the invasion fleet that included the mission's four carriers. At dawn on June 4, Nagumo sent off nine squadrons of bombers escorted by four squadrons of Zero fighters. Their arrival at Midway was expected to be a surprise. Instead, the planes were met by heavy antiaircraft fire and a fierce swarm of game but outmoded and outclassed fighters.

Nagumo's Zeros shot down most of the U.S. planes. Overall, however, the initial resistance put up by Midway's defenders seemed to the Japanese leader of the raid too strong to permit a landing of troops. He radioed back to his commander that a second attack wave was needed.

That was not what Nagumo wanted to hear. His ordnance men were already arming aircraft with torpedoes and armor-piercing bombs, preparing to dispatch any Allied warships that might show up, especially the U.S. carriers that Yamamoto hoped to lure toward Midway. A second attack on the island meant canceling that order and equipping his planes with fragmentation bombs for a land bombardment. The necessity for the change, however, seemed to be confirmed by the arrival of a fleet of torpedo bombers from Midway. Even though antiaircraft fire and the Zero fighters massacred the obsolete U.S. planes, their attack verified that the defenders of Midway were far from neutralized. Nagumo sent off a second wave against the island.

While those planes were in the air, he received dumbfounding news: one of his reconnaissance planes had discovered American warships in the area. At first the spotter saw only cruisers and destroyers. Then he reported a carrier. He also warned that more torpedo planes were winging Nagumo's way. How should he counter this incredible new development? After dithering for a precious quarter of an hour, Nagumo ordered that the returning planes be armed with the original torpedoes and bombs to be used against surface ships.

At that moment of maximum confusion and vulnerability, when the Japanese carrier decks were cluttered with torpedoes, bombs, gasoline hoses and aircraft, came what Gordon Prange in his monumental Miracle at Midway called the Americans' "uncoordinated coordinated" attack.

Spruance and Fletcher had planned for flights of torpedo planes, dive-bombers and fighters to converge simultaneously over the Japanese fleet, while Flying Fortresses from Midway dropped their bombs from great heights. But Nagumo had changed course, and the American planes had trouble finding his ships. The fighters, running out of fuel, turned back, many of them having to ditch. The torpedo planes, first to discover the Japanese, courageously swept in at low levels. The complete flight was shot to pieces by the Zeros, with only one of the thirty crewmen surviving. They were lost without scoring a hit. The Flying Forts were equally ineffective, managing nothing better than near misses.

The sacrifice of the torpedo planes, though, was not in vain. While the Zeros were occupied with them down near sea level, thirty-seven American dive-bombers from Enterprise arrived far overhead. They had traced their way to Nagumo's fleet only because their commander, Clarence Wade Mc-Clusky, had cannily let himself be guided by a Japanese destroyer returning after a try at sinking a pesky U.S. submarine. When McClusky and his mates went into their screaming dives, the huge rising suns painted on the flight decks as aids to Japanese fliers gave the Americans perfect targets. McClusky's crew wrecked the Akagi and the Kaga. A second flight of  dive-bombers, from Yorktown, arrived almost simultaneously and concentrated on Soryu.

In less than five minutes the opportunity that had been slipping away from the Americans was turned into a flaming victory. Three of the four carriers were reduced to blazing hulks and later sank. As historian Keegan put it, "Between 10:25 and 10:30, the whole course of the war in the Pacific had been reversed." George Marshall called it "the closest squeak and the greatest victory."

The battle was not quite over. The Yorktown, only partially restored from her Coral Sea mauling, was further crippled by a flight of Japanese dive-bombers from the remaining carrier and was finished off by a submarine, which also sank a destroyer. Bombers from Enterprise exacted quick revenge. Her planes caught up with the retreating occupation force and sank the fourth carrier. Also, one cruiser was sunk and a second badly damaged.

Yamamoto still had a vast superiority in sea power, but with the only other two carriers of his fleet protecting the Aleutian landings, he knew he was defeated. He called off the Midway operation and sneaked back to home waters.

The one part of Yamamoto's overly complex plan that succeeded was his diversionary raid against the Aleutians. Ironically, his small victory there came about because Theobald, the American commander, refused to believe what his cryptographic team told him. Their decrypts warned that while the Japanese would bomb the American base at Dutch Harbor, they would land troops to seize Attu and Kiska. Theobald would not be swayed from believing the invasion would be against Dutch Harbor, and he positioned his ships accordingly. When Yamamoto's attackers did exactly what the decoders had forecast, Theobald's task force was in the wrong place by a thousand miles. It failed to prevent the Attu and Kiska landings.

Otherwise, the great surge of Japanese expansion was over. After Midway, despite a few abortive efforts to mount new drives, the war machine of the Rising Sun was put on the defensive.

"Midway was essentially a victory of intelligence," Nimitz later wrote. George Marshall added that as a result of cryptanalysis, "we were able to concentrate our limited forces to meet their naval advance on Midway when otherwise we almost certainly would have been some 3,000 miles out of place."

At a postbattle staff conference at Pearl Harbor, Admiral Nimitz singled out Joe Rochefort: "This office deserves a major share of the credit for the victory at Midway."

One result of the battle nearly caused disaster for the codebreakers. Along with accounts in the American press exulting over the Midway victory was a sidebar story that caused U.S. cryptographic teams consternation and dismay. The story's headline was NAVY HAD WORD OF JAP PLAN TO STRIKE AT SEA. Appearing in three large dailies owned by Roosevelt-hating Colonel Robert McCormick, the story related that navy commanders knew in advance about Japanese plans, the strength of their forces and the fact that a move against "another base" was only a feint. The gaffe could have cost the Americans their entire intelligence advantage over the Japanese. Investigations found that a reporter aboard American ships in the Pacific had been allowed to see U.S. intelligence summaries and had, with remarkable insensitivity, filed his account, to which equally obtuse censors had given approval. Whether because of this break or as the result of their natural precautions about cryptographic security, the Japanese did make changes in their codes that Allied codebreakers had difficulty in overcoming.

 

 

Countering New Drives on Port Moresby

 

Douglas MacArthur adopted a complex attitude toward codebreakers. His powerful ego and adherence to old army values caused him to project the image that reliance on such undercover chicanery was beneath him. In making his decisions he needed no other source of advice than his own superior brain. His sycophantic staff, revering him as "The General," followed by practicing a studied "negligent indifference" toward signals intelligence. Yet he was too shrewd a commander, and they were too intent on seeing him win, not to make use of the advantages the codebreakers provided.

After their escape from Corregidor in late March 1942, MacArthur set up his cryptographic team, together with an Australian unit and a British contingent from Singapore, as the nondescriptly named Central Bureau in Brisbane. His real attitude toward signals intelligence, as Edward J. Drea has pointed out in his book MacArthur's Ultra, was indicated by the fact that one of his first appeals to the War Department was for cryptanalytic support. In his study MacArthur as Military Commander, Gavin Long commented about The General, "The prescience with which he may at times seem to have been endowed was generally the outcome of the cracking of Japanese codes."

Intelligence informed him that the Imperial forces had decided on two new campaigns against Port Moresby. An overland drive would be made across the Papuan southeastern sector of New Guinea. In addition, decodes revealed that the Japanese would try to take the port in a new seaborne invasion.

The overland campaign was launched first. On July 22 the Japanese began unloading at Buna, on the northern coast of New Guinea, the army division that had been turned back in the Coral Sea battles. The troops faced a formidable obstacle: the Owen Stanley Range, thirteen thousand feet high and almost constantly immersed in rain clouds. The sole passage was by the Kokoda Trail, hewed through the jungle and up and over the mountains, so narrow that in places only men walking in single file could traverse it. The hot, humid climate and incessant pounding rain turned the trail into a seventy-eight-mile-long horror of ankle-deep muck and slippery roots, the scene of what Morison called "the nastiest fighting in the world."

The troops sent in by the Japanese were crack infantry, trained in jungle warfare, their supplies carried on the backs of New Guinea natives. Driving the Australian defenders steadily before them, they came within sight of Port Moresby. There the determined Aussies, aided by rushed-in American GIs, dug in and stopped the advance. The battle dragged on for days, then weeks, while Allied planes smashed Japanese attempts to replenish their troops. In the end, the starving, disease-ridden remnants of the Japanese force retreated back to Buna.

Yamamoto's new sea campaign against Port Moresby concentrated first on taking the anchorage at Milne Bay, on the southeastern tip of New Guinea. The Australians had a small garrison there and had constructed an airfield. Yamamoto wanted the airfield to provide air cover for his landings at Port Moresby.

Allied decodes informed MacArthur of this new threat. He quickly reinforced the troops at Milne Bay and had his new air commander, Major General George C. Kenney, organize his meager forces into as strong a defense as he could manage. The aggressive Kenney directed preemptive air strikes against Japanese airdromes at Rabaul and Buna, greatly reducing the number of planes they could send to protect the landing at Milne Bay.

Lacking the equivalent of the Allies' codebreaking, the Japanese expected only a minimal defense of the port. On August 24, 1942, they sent in a landing force composed of overage recalled reservists. When this group was shot to pieces and radioed for help, a special Naval Landing Force went in. They fared no better. After another week of bitter fighting, the Japanese gave up. The Melbourne cryptanalysts deciphered the Imperial Navy's order for the evacuation of Milne Bay.

Yamamoto's grand design of using Port Moresby as a base against Australia was frustrated. In contrast, MacArthur brought a new spirit to the Australian people. On his arrival he had found a nation cowering in fear of conquest. Some among Australian military leaders had been convinced they must be ready to surrender the continent's less populated areas in the hope of holding the more populous parts. MacArthur rejected their pessimism, signaling his aggressive attitude by announcing that he meant to make his base of operations not in the relative safety of Melbourne or Brisbane but at Port Moresby. "We'll defend Australia in New Guinea," he proclaimed.

In view of MacArthur's successes at Milne Bay and Port Moresby, which supplemented the victory in the Coral Sea, the Aussies took heart that The General might well deliver on his promise.