It was Japan's assault on China that ultimately provoked the clash with the Allies. In the summer of 1941, United States President Franklin D. Roosevelt, in response to Japanese aggression on the Asian mainland, ordered an embargo against Japan. This embargo included oil and other strategic materials that Japan, an island nation with limited indigenous natural resources, needed to import. President Roosevelt didn't intend to back Japan into a corner, but that's what he did. For the military ruling Japan, the embargo meant a choice between ignominious retreat from China, or a suicidal war with American. They chose war. General Hideki Tojo was named Prime Minister and formed a War Cabinet.
Admiral Isoroko Yamamoto, Commander-in-Chief of the Imperial Japanese Navy's Combined Fleet, came up with the audacious, and to the Americans, treacherous, surprise raid on Pearl Harbor. Pearl Harbor in the Hawaiian Islands was the US Navy's main Pacific Base. On the morning of December 7th, 1941, planes from the Japanese Kido Butai, or Striking Force, composed of the large carriers Akagi, Kaga, Zuikaku, Shokaku, Soryu, and Hiryu, found the battleships of the US Pacific fleet asleep at anchor. Surprise was complete, and within minutes, the ships the US Navy had expected to be its main offensive weapons were burning wrecks sinking into the harbor mud.
On the other side of the Pacific, Japanese ships and troops quickly overwhelmed the meager Allied naval forces, and began landings to secure the strategic resources denied them by the embargo. Within weeks, Borneo, Java, Singapore and the Philippines had fallen. Imperial forces captured and reinforced a string of defensive outposts including Wake, Tarawa, Rabaul and Hollandia. The Striking Force raided deep into the Indian Ocean, hitting Ceylon and Port Darwin.
Yorktown limped back to Pearl Harbor for emergency repairs, and then joined Enterprise and Hornet in setting an ambush at Midway. The US had broken the Japanese Navy's secret code, and Nimitz was tipped off that Yamamoto, in response to the Doolittle Raid, was seeking to force a showdown with the USN at a minor speck of land in the very middle of the Pacific, Midway Island. Yamamoto brought the bulk of his fleet, including four of the big carriers that had pounded Pearl Harbor half a year ago. He thought by attacking Midway, he would draw the the US fleet into a trap where it would be annihilated. Nimitz turned the tables on him. In early June 1942, nearly seven months to the day after Pearl Harbor, US pilots sent Akagi, Kaga, Soryu and Hiryu to the bottom of the Pacific in one of the most pivotal naval battles in history. Hiryu lived long enough for her pilots to consign Yorktown to her own doom, but Japanese Naval airpower had been shattered.
The Japanese sought to reinforce their troops on Guadalcanal from their major base at nearby Rabaul. The Allies did likewise from Espiritu Santo. A series of battles, both surface duels at night and carrier battles in the day, raged around the island. The waters off Guadalcanal became known as Ironbottom Sound for the number of ships sunk there, many by the dreaded Japanese Long Lance torpedo. But Allied control of Henderson Field on Guadalcanal allowed them to eventually defeat the Japanese and control the island. By the time the Japanese evacuated Guadalcanal in February of 1943, they had lost a light carrier, battlecruisers Hiei and Kirishima (both veterans of the Pearl Harbor raid), and 2 heavy cruisers. The Allies had lost carriers Wasp and Hornet, along with 8 cruisers. Several Admirals on both sides joined the ships and men under their command who never returned from the waters around The Canal. Again, despite the imbalance in the number of ships lost, the Allies won the battle, driving the Japanese back. Guadalcanal would mark the point of farthest expansion for Imperial Japan. From there, it was nothing but retreat.
From Guadalcanal and Port Moresby, the Allies began a two-pronged assault driving the Japanese back. Nimitz moved up the Solomon's chain while General Douglas MacArthur drove along the northern coast of New Guinea. The original plan had been to take the major Japanese base at Rabaul, but instead US airpower pounded Rabaul into rubble, and the Japanese garrison was cut off and isolated, to wait the rest of the war for an invasion that never came.
During the Solomon's campaign, while on an inspection tour of Japanese defenses, Admiral Yamamoto was killed when his plane was intercepted and shot down by American fighters over the jungles of Bougainville.
Truk, the formidable Japanese base in the middle of the Pacific, felt their wrath in February. The devastation was complete, a measure of payback for Pearl Harbor, and the IJN never again used Truk as a base for large ships. Like Rabaul, Truk was isolated, destroyed, and bypassed. Allied troops set their sights deeper in the Japanese empire.
The Marianas were next. In June of 1944, Saipan was invaded, followed by Guam and Tinian in July. It was here in the Marianas, with the support of hundreds of land-based planes that the IJN prepared for a 'decisive battle.' Vice Admiral Jisaburo Ozawa, the new IJN C-in-C, concentrated the bulk of Japan's remaining naval strength, nine carriers, five battlewagons and eleven heavy cruisers, to oppose the landings at Saipan. Against him, Admiral Raymond Spruance had the cream of the Allied fleet, 15 carriers, seven battleships and eight heavy cruisers. Allied aircraft outnumbers the Japanese two-to-one, and at this point of the war, the allied pilots far surpassed their Japanese counterparts in skill and experience, the best Japanese pilots having long ago perished in the brutal war of attrition Japan was losing to the allies.
In June of 1944, the Battle of the Philippine Sea, the largest carrier battle in history, put an end to Japanese naval airpower in what became known as 'The Great Marianas Turkey Shoot.' The Japanese lost over 300 planes and two carriers, including veteran Shokaku. On the other side, the Allies lost 30 planes and no large ships.
With the Marianas secured, the Allies now had bases for the new long-range B-29 bombers. Soon, Japanese cities would suffer the effects.
In a complex plan, Ozawa split his ships into three forces. A Northern Force of carriers, depleted of aircraft, would serve as a decoy to draw off Halsey, while two task forces built around battleships, including the super battleships Yamato and Musashi, would converge on the landings and destroy the Allied invasion fleet. Unlike most of the overly complex plans the IJN was so fond of, this one actually worked. Almost.
The Center force, under Vice Admiral Kurita, came under attack first. Two CAs were sunk and a third disabled by submarine attacks, then the survivors were set upon by 250 planes from Halsey's carriers. Kurita had no air cover of his own, and Musashi was sent to the bottom by 19 torpedoes and 17 bomb hits.
Farther south, Vice Admrial Nishimura's Southern Force, built around BBs Fuso and Yamashiro and CA Mogami, ran into Rear Admiral Jesse Oldendorf's six battleships. Five of them, California, Tennessee, West Virginia, Maryland and Pennsylvania, were survivors of Pearl Harbor, raised from the mud and refitted for vengeance. They got it, wiping out Nsihimura's force.
At this point, Ozawa's Northern Force finally drew the Allies attention. Thinking the Center force turned back and the Southern force sunk, Halsey steamed north after Ozawa's empty carriers, sinking Zuikaku, the last survivor of the Striking Force that hit Pearl Harbor. But before Halsey could annihilate the remainder of Ozawa's force, he had to turn back towards the beaches at Leyte, because Kurita's Center Force had not in fact withdrawn. They had continued onward, and ran smack into a collection of US Destroyers and Escort Carriers, small, slow flattops meant to support landings and conduct anti-submarine patrols, not engage enemy warships. This small force, known as Taffy 3, found itself under the guns of four Japanese battlewagons and six heavy cruisers. They were the only thing between Kurita and the vulnerable transports. Despite being heavily outgunned, Taffy 3 under Rear Admiral Clifton 'Ziggy' Sprague, charged the Japanese ships, sinking three cruisers and so rattling Kurita that he finally did withdraw. The Allied landings continued, and the liberation of the Philippines moved forward.
It was the largest naval battle in all of history, and the last time the Imperial Japanese Navy was able to fight as a cohesive unit. But the war dragged on. In February 1945, the Allies landed on Iwo Jima, unopposed by any Japanese surface units. In April they landed on Okinawa, and the IJN launched its final sortie, sending the gigantic Yamato on a suicide mission with only enough fuel for a one-way voyage. Admiral Spruance, commanding the Fifth Fleet sent his carrier aircraft after the Yamato, and in under two hours of continuous air attack dispatched the giant to the bottom of the sea. The Imperial Japanese Navy was finished.