Turned the Tide in the Second World War (2013)
It seemed to be all wine-and-roses for Japan until July 1941, when the US, Britain, and the Dutch froze all of Japan's commercial assets, essentially cutting off Japan's imports of oil (of which Japan imported 88%). The Empire of the Sun could either buckle or strike out to gain what it needed to supply their home islands and its war machine. The leaders of Japan believed that if they gave in to the US/British/Dutch, their nation would revert back to a medieval state. That scenario was totally unacceptable to that generation of Japan's military leaders, such as Nagumo, Tojo, and Yamamoto (all three served their nation in WW I).
Japan's most decisive act WAS NOT their attacks on 7-8 December 1941 on Pearl Harbor, the Philippines, and Hong Kong, but their invasion of mainland China in 1937. Everything else that followed was of operational or diplomatic consequence, including closer ties with Nazi Germany, neutrality with the USSR, moving into Southeast Asia, going for oil in the Dutch East Indies, and taking Hong Kong and Singapore. As far as the attack on Pearl Harbor, Japan wanted to prevent any US advance in the Pacific, especially south . . . the main cause of all that occurred in the Pacific before and after 7/8 December 1941 was Japan's invasion of China in 1937.
Japan had a strong army that was oriented toward conquest on the Asian continent, as well as dealing with Russia . . . the US/British were of much less interest to the Japanese military until the economic blockades. The Japanese army was large and disciplined, and very well-trained with modern weapons, but had little interest in fast armored warfare (e.g. tanks). The Japanese army had a tremendous focus on sea-to-land warfare, crossing rivers, warfare in jungles and mountains; taking distant islands in the Pacific was not yet a priority. Japan saw no point in creating an expensive long-range strategic bombing force, since there weren't any real strategic targets to bomb in Shanghai or Vladivostok.
Therefore, by June 1942, Imperial Japan had overstretched itself in the Pacific and Asia, and had even put most of their troops in the wrong places, but didn't realize their strategic blunders. Japan had achieved great territorial gains, the nation was safe, and the booty from its conquests were pouring in to the home islands, and there were no breakthrough counter-attacks by the US/Great Britain. So, to Imperial General Headquarters, the situation in June 1942 was not disastrous, or even serious. The loss of four aircraft carriers at Midway was "regrettable", and the loss of Guadalcanal seemed too distant to matter. By the end of 1942, alarm bells were not ringing at Imperial General HQ, and by the end of 1943, they only heard the alarm bells at a distance.
There were four alternatives that were debated at the highest levels in the US Military as to the main strategy in the Pacific. One option was to base the Allied counter-offensive on mainland China. A second option was to focus on SE Asia, and a third was to focus in the SW Pacific from Australia north to the Philippines. The last option that was debated was "Island Hopping" in the Pacific, taking key Japanese island strongholds, shrinking their defense perimeter. In the end, only one option in the Pacific would work: Admiral Nimitz's thrust of the US Navy across the Pacific ("Island Hopping") in order to take islands close enough to be able to strategically bomb Japan into surrender. The other three options were ancillary or secondary to the US Navy and the Marines, much to General Douglas MacArthur's immense irritation in the SW Pacific.
By 1942, it was obvious that only the US could end Japan's domination of the Central, West, and South Pacific. American munitions factories were mostly located on the West Coast at about the same latitude as Japan, and there was no intervening land between San Francisco and Tokyo. It made sense to advance on a line that was somewhat south of the Tropic of Cancer, from Hawaii to the Gilbert and Marshall Islands, then to the Carolines, and then the prize, the Marianas, before turning north to Japan. Hawaii gave the US control of the Central Pacific, not only as a bulwark against Japanese expansion, but also as a launching point for a massive counter-offensive.
The attack on Pearl Harbor opened the US Navy's eyes (as well as the US Gov't) to the amazing destructive reach of a carrier group . . . they were determined to use that strategy against Japan. Third was the development of the B-29 Superfortress, a bomber so advanced that not only could it carry and immense bomb load thousands of miles, but it could fly at an altitude of 30,000 feet, which meant it could not be attacked by enemy fighters or ant-aircraft shells. Once the Marianas were taken and secured from Japan, B-29 airbases provided an enormous advantage to end the war sooner.
During 1943-1945, only the US could have built the B-29; Hitler called the Superfortress a "Wonder Weapon". The wiring/aluminum for a B-29 equaled that of a squad of Messerschmitts. Fourth were the Seabees, the US Navy Construction Battalions; the Seabees were the engineers that created what was needed in the face of geographic challenges. And fifth, the US Submarine Service within the Navy . . . what was needed was command and organization to bring all the elements together in order to defeat Japan.
Together, they tipped the balance in the Pacific in part because they came into full service in the middle of the crucial period of mid-1943 to early-1944, just when the US counter-attack was gaining momentum. Both complemented the other, with the Hellcat being a great defender of the carriers that launched them, as well as being an absolute terror to Japanese forces.
There were many turning points in the Pacific, such as Guadalcanal and Midway; a turning point that to this day has been under the radar occurred 30 May 1943, when the USS Essex arrived at Pearl Harbor. The Essex was the first of the brand-new, tough, powerful and sophisticated aircraft carriers that would make a huge impact in the Pacific. The new Yorktown (named in honor of the original) arrived in late-July 1943 with some of the new light carriers. The Essex-class carriers proved to be superior to Japanese carriers; the weapons system was a miracle. The new US carriers had radar-controlled gunnery and detection, armored hangars, and were capable of speeds up to 30 knots, and have 90-100 planes.
A total of 31 Essex-class carriers were on order in 24 gigantic shipyards. The new carriers were going to Admiral Chester Nimitz in the Central Pacific, not to MacArthur in the SW Pacific, in order to increase the odds of taking key islands. An added benefit: the US Navy would have time to plan how to use the new Essex-class carriers. It was decided to cluster the carrier groups in order to make the more effective; hundreds upon hundreds of aircraft would be able to descend on Japanese carriers/ships, plus the ability to defend the carrier groups was greatly increased.
The B-29 weighed twice that of a B-17 Flying Fortress; its pressurized cabin meant altitudes up to 30,000 feet, and its maximum airspeed was 350 mph. The B-29's over Japan unleashed brutal, unprecedented devastation in that part of the world. The most destructive runs of the B-29's were the low-flying firebombings of Tokyo in March 1945; 130,000 Japanese were killed - the Tokyo firebombing occurred at the same time as the firebombings in Western Europe (e.g. Dresden).
The B-29 was a very complicated weapon, which featured a great number of difficult development problems. The only runways for the 141 foot wingspan and the 120,000 pound weight existed in specifically-designed runways that were only in the Pacific. At Boeing, the Design-and Development teams had their abilities and imaginations stretched to the limit. Major problems included how to pressurize different cabins but not the bomb bays; designers created a pressurized "crawl tunnel" that linked the cabins. The biggest problem was with the engines; all the early engines were inadequate and unreliable. The B-29 project was almost scrapped due to the seemingly insurmountable obstacles, but General "Hap" Arnold kept the program going.
Even when the B-29 was completed, it was the devil to get a B-29 to successfully take-off; even the Enola Gay came close to running out of runway. But once the B-29 reached its desired altitude, it was untouchable . . . the only real threats were within the B-29 itself, with its complex mechanisms that needed to work flawlessly in concert with each other.
The US surge in the Pacific occurred later than that of the Allies in Western Europe, since the "tools of war" took longer to develop and produce in large numbers. But once assembled, the US counter-attack in the Pacific went remarkably fast. Even in the extreme early stages of the US counter-attack, in one day at Guadalcanal, 11,000 of 19,000 Marines landed without immediate opposition, quickly gaining the upper-hand.
The US Navy and Marines learned much in the months after the disastrous victory at Tarawa. The Marines had figured out their amphibious-warfare techniques, the Essex-class carriers and groups were in place, the F6F Hellcats were aloft, the Seabees were building, and the B-29's were bombing Japan. The single-most important amphibious operation in the Pacific occurred on 15 June 1944, when 127,000 US troops, mostly Marines, began to land on the Mariana Islands; it was far-more threatening to Japan than anything MacArthur's forces were accomplishing in the SW Pacific. The US had acquired the islands that were close enough in order to bomb Japan into submission and surrender.