The storm of iron and explosives that broke over Pearl Harbor on Dec. 7, 1941, was one of the finest applications of air power in all of World War II. For several hours on that beautiful Sunday morning in Hawaii, Japan’s elite naval aviators pummeled the American forces on Oahu, crippling the U.S. Navy’s battleship fleet and destroying the ability of the United States to intervene against other Japanese occupation efforts in the Pacific Basin. The Hawaiian operation was a flawed concept from the start, however, targeting only enemy naval vessels and aircraft, missing more strategically significant targets, and setting the stage for Japan’s eventual defeat in 1945. Despite this, the attack on Pearl Harbor remains one of the most intriguing and decisive air strikes in history.
The Japanese: Forces and Plans
U.S. Navy Commodore Matthew C. Perry’s four-ship diplomatic mission to Japan in 1854 triggered the island nation’s emergence from centuries of isolation under the xenophobic Tokugawa shoguns (1603-1868). Within two generations, the Japanese transformed their preindustrial society to catch up with and even surpass the most advanced military technology of the Western powers. During that period, the Japanese developed a complex love-hate relationship with America and its society. This was symbolized by President Theodore Roosevelt’s intervention to help negotiate the Treaty of Portsmouth, (which ended the Russo-Japanese War in 1905) at the same time that racial segregation was imposed on Japanese-American immigrants in California’s schools. Nevertheless, during World War I, Japan joined the Western Allies, and was rewarded with a number of former German colonial possessions in China and Polynesia.
By the 1920s, Japanese elites began to believe that the domination of the Pacific Basin was the natural expression of their national manifest destiny. However, the emerging civility of nations following World War I put a crimp in Japan’s plans for regional dominance. In particular, the wave of naval disarmament treaties (London in 1920 and Washington in 1922), designed to reduce the chances of war, actually offended the Japanese due to the Western powers’ insistence that they accept an inferior and unequal status. Japan’s total warship tonnage was limited to three-fifths of the American or British fleets, leaving the Pacific in an uneasy stasis. During the 1930s, the West increasingly viewed Japan’s “expansion” in China as “aggression,” and a collision of vital interests became inevitable. Meanwhile, in deep secrecy, a generation of brilliant young Japanese engineers and naval officers was perfecting a well-trained naval aviation force, equipped with fast carriers, long-range aircraft, and the best torpedoes in the world.
In August 1939, Adm. Isoroku Yamamoto became commander in chief of the Imperial Japanese Navy and began planning for war with the United States. A visionary with an eye to the growing power of naval aviation and aircraft carriers, he was a “transformation” supporter long before the term was created. This was important, since the major navies of the late 1930s were dominated by the cult of the battleship. Called the “Big Gun Club,” it was composed of senior officers who had spent their careers training and preparing for dramatic and decisive gunnery duels between armored dreadnoughts. For more than two decades, naval war colleges around the world had spent time refighting and analyzing the Battle of Jutland, all seeking to find ways to achieve decisive victory through the guns of battleships.
Yamamoto was determined to strike the U.S. Pacific Fleet, which had relocated in spring 1940 from its traditional bases at San Diego and Long Beach, Calif., to Pearl Harbor on the island of Oahu.
All of this changed on the night of Nov. 11, 1940, when 21 slow Swordfish torpedo bombers launched from the Royal Navy aircraft carrier HMS Illustrious struck the Italian naval base of Taranto. The fragile British biplanes sank three modern battleships with aerial torpedoes, damaging two cruisers as well.
Yamamoto was determined to strike the U.S. Pacific Fleet, which had relocated in spring 1940 from its traditional bases at San Diego and Long Beach, California, to Pearl Harbor on the island of Oahu. The Japanese regarded this forward deployment as a deliberate provocation.
Yamamoto’s finely tuned instrument for the Hawaii operation was the Kido Butai (literally, “Mobile Force”), commanded by Vice Adm. Chuichi Nagumo and built around six large aircraft carriers (Akagi, Kaga, Hiryu, Soryu, Zuikaku, and Shokaku) of the “First Air Fleet.” The First Air Fleet pilots and crew trained for months to attack the American fleet at anchor in Pearl Harbor, along with the combat planes on airfields scattered around Oahu. As they trained, Japanese engineers and designers worked on producing the special weapons necessary to attack ships in a confined harbor. Specifically, this included shallow-running aerial torpedoes and heavy armor-penetrating bombs to hit the battleships and aircraft carriers they hoped to find moored alongside Ford Island in the middle of Pearl Harbor. By late November 1941, all preparations were complete, and the Japanese task force was ready for its journey across the Pacific.
For what the Japanese called “the Hawaiian Operation,” Kido Butai was escorted by the fast battleships Hiei and Kirishima, the heavy cruisers Chikuma and Tone, and screened by a light cruiser, nine destroyers, and three long-range submarines. Eight oil tankers accompanied the strike force on a long, indirect approach across the rough, foggy, and nearly untraveled North Pacific (mostly along the 43 degree north latitude line).
By late November 1941, all preparations were complete, and the Japanese task force was ready for its journey across the Pacific.
In total radio silence (“transmit” keys were removed or sealed on every radio of the force), the fleet sailed from Tankan Bay in the remote Kurile Islands on Nov. 26. Its advance was shielded from observation by a weather front that was moving about the same speed across the North Pacific. The voyage took almost two weeks, during which time other Japanese invasion and attack forces moved toward their targets. During the same period, Japanese diplomats continued to negotiate with the United States, in part to screen Kido Butai from U.S. curiosity. All the while, Takeo Yoshikawa, a secret agent at the Japanese Consulate in Honolulu, provided daily coded updates on the types and locations of the American warships in port.
To support the planned attack, 20 Japanese fleet submarines patrolled around the Hawaiian Islands to ambush any U.S. forces that might escape the aerial attack. At the same time, a “Special Naval Attack Unit” (under Capt. Hanku Sasaki) of five two-man midget submarines launched from submarine mother ships was dispatched on a direct course to Pearl Harbor. The midget subs would attempt to enter the narrow, net-protected channel by trailing one of the minesweepers that routinely patrolled the harbor entrance.
The First Air Fleet massed a total of 474 aircraft: 137 fighters (Mitsubishi A6M2 Type 0 “Zeros”), 144 dive-bombers (Aichi D3A1 Type 99 “Vals”), and 183 torpedo planes (Nakajima B5N2 Type 97 “Kates”). The Japanese aircrews were products of an incredibly tough selection process and a rigorous training program. Originally, Yamamoto had considered launching the Pearl Harbor strike as a one-way mission from a range of 500 miles, but his staff convinced him that the sacrifice of so many irreplaceable pilots and aircraft was unnecessary to achieve surprise. Many of the Japanese naval aviators were veterans of recent combat over China, leading a crack corps of flyers into a target they knew as well as their own home bases. One measure of their skill is that using only the simplest optical sights, the torpedo and dive-bomber pilots would achieve hit rates at Pearl Harbor that would not be equaled until laser-guided munitions entered combat in the 1970s.
Three hundred and sixty-one of Japan’s best pilots were handpicked for the Pearl Harbor attack. The Val dive-bombers carried semi-armor-piercing bombs, with excellent blast and fragmentation effects. Some of the Kates would carry special armor-piercing bombs converted from 16-inch naval gun projectiles. The rest of the torpedo planes carried the superb Type 91 aerial torpedo (17 3/4-inch diameter with a 205-kilogram/452-pound warhead), modified with special wooden fins for low-level drops into shallow water.
The strike was organized in three groups, requiring precise calculation of timing, distance, speed, wind, and aircraft endurance. Time-on-target and complete synchronization were critical to help manage the air traffic over the carrier decks and maximize the effectiveness of the attacking aircraft.