All the details of the Japanese attack on Pearl Harbor were very well thought out. First of all, in the formation of troops, it is necessary to have a strong assault power, and at the same time, it is necessary to avoid the formation being too large and being discovered. In the end, it was determined that there were 6 aircraft carriers, 2 battleships, 2 heavy cruisers, 1 light cruiser, 11 destroyers, 3 submarines, and 8 oil tankers, a total of 33 ships. There are a total of 423 carrier-based aircraft, of which 354 are responsible for assault missions, including 131 Type 99 dive bombers, 104 Type 99 horizontal bombers, 40 Nakajima B5N2 Type 97 torpedo planes, 79 Mitsubishi A6M2 Zero fighters, and the remaining 69 planes are responsible for protecting the safety of the formation.

The commander of the assault formation is Vice Admiral Nagumo Tadaichi, and it has six units under its jurisdiction: an air attack force, which is under the direct command of Nagumo, and includes six aircraft carriers, the "Akagi," the "Kaga," the "Soryu," the "Flying Dragon," the "Shozuru," and the "Zuizuru," and the mission is to dispatch carrier-based aircraft to attack the US battleships and aircraft carriers anchored at Pearl Harbor.

The alert force, commanded by Rear Admiral Sentaro Omori, commander of the 1st Destroyer Squadron, was composed of the light cruiser "Abusumi" and nine destroyers, the "Tanikaze", "Urakaze", "Hamakaze", "Isokaze", "Shiranui", "Kasumi", "Hail", "Yangyan", and "Akiun", and was responsible for providing alert for air raid units and supply units.

The support force, commanded by Vice Admiral Mikawa Gunichi, commander of the 3rd Sentai Force, consisted of two battleships, the "Hiei" and "Kirishima", and two heavy cruisers, the "Tone" and "Chikuma", which were responsible for providing support to the air attack forces, mainly against the large surface warships of the US army.

The patrol force, commanded by Admiral Osa, commander of the Second Submarine Group, Izumi Izumi, and composed of three submarines, the "I-19," the "I-21," and the "I-23," sailed ahead of the formation route and was responsible for reconnaissance and vigilance.

The Midway Raid Force, commanded by the commander of the 7th Destroyer Group, Konishi Dignita, and composed of two destroyers, the "Tide" and the "Ripple" and the supply ship "Shiriya," was tasked with shelling Midway to contain the US forces.

The supply force, consisting of seven oil tankers, including the "Polar" Maru, the "Far Eastern" Maru, the "Kenyo" Maru, the "Kokuyo" Maru, the "Shenguo" Maru, the "Toho" Maru, the "Toei" Maru, and the "Japan" Maru, was responsible for refueling the formation at sea.

The advance formation was commanded by Vice Admiral Mitsumi Shimizu, commander of the Sixth Fleet, and set off ahead of the assault formation, with six units under its jurisdiction:

The No. 1 Submarine Force, commanded by Rear Admiral Tsutomu Sato, commander of the No. 1 Submarine Squadron, has four submarines under its command, the "I-9," the "I-15," the "I-17," and the "I-25," and is deployed northeast of Oahu to attack US ships that may launch counterattacks.

The Second Submarine Force, commanded by Rear Admiral Shigeki Yamazaki, commander of the Second Submarine Squadron, has seven submarines under its command, namely "I-1," "I-2," "I-3," "I-4," "I-5," "I-6," and "I-7," and is operating in the Kauai Strait and the Kayiwe Strait between Oahu, Kauai, and Molokai to monitor and wait for an opportunity to attack the US forces.

The Third Submarine Force, under the command of Rear Admiral Shige-Miwa of the Third Submarine Squadron, has nine submarines under its command, namely the "I-8," "I-68," "I-69," "I-70," "I-71," "I-72," "I-73," "I-74," and "I-75," and is operating in the waters south of Oahu to attack US warships that may launch counterattacks.

The special attack force, commanded by the commander of the Third Submarine Group, is under the command of Commander Sasaki Hanjiu Naval Officer, and has under its jurisdiction five submarines, the "I-16," the "I-18," the "I-20," the "I-22," and the "I-24," each carrying one pocket submarine.

The reconnaissance unit consisted of two submarines, the "I-10" reconnoitring Fiji and Samoa Islands, and the "I-26" reconnoitering the Aleutian Islands.

The supply force, consisting of six oil tankers, "Hidden Household" Maru, "East Asia" Maru, "Shintamama" Maru, "Otoyo" Maru, "Hitachi" Maru, and "Mt. Fuji" Maru, was deployed on the mainland and in the Kwajalein Islands to provide fuel supply for the submarines of the advance force.

In order to ensure the close coordination of the two formations, Yamamoto stipulated that Nagumo would be under unified command until four days before the start of the attack. In terms of route selection, there are usually three routes from mainland Japan to Pearl Harbor: one is the northern route through the Aleutian Islands; the second is the middle route via Midway; The third is the southern route through the Marshall Islands. Each of these three routes has its own advantages and disadvantages, the northern route is far away from the patrol range of US shore-based air forces, and there are generally no merchant ships sailing, which is convenient for concealment. However, the climate is harsh, the wind is strong, and it is difficult to refuel at sea. The climate of the central and southern routes is suitable for navigation, but there are frequent merchant ships coming and going, and they are relatively close to the US islands, so they are easy to be discovered by the US military. After repeated comparisons, especially for the sake of secrecy, the Japanese finally chose the northern route.

The advance formation is composed entirely of submarines and can go to the battlefield in concealment, so there is no prescribed route, and it is only required to avoid the patrol of US shore-based aircraft.

The distance to the sea area where the assault aircraft group took off was also taken into account. Too close is easy to be detected, too far away will make the pilot tired and affect the battle. After several studies, the take-off sea area was finally selected as 200 nautical miles (about 370 kilometers) north of Oahu, that is, 42 - north latitude and 170 - west longitude. According to the speed of the Japanese planes at that time, it took about two hours from takeoff to arrival at Pearl Harbor. And after the carrier-based aircraft took off, the aircraft carrier retreated some distance. In this way, the Japanese planes had a short range when they went and a slightly longer range when they returned. If the US military sends planes to pursue it, then the round-trip flight range will increase considerably, making it more difficult for the US military to pursue.

The Japanese side chose Sunday as the time to launch the attack, because according to the law of US military activities, warships that go to sea usually return on Saturdays, so the most warships are anchored in the harbor on Sundays, and the most personnel are on vacation on Sundays, and their vigilance is the most lax. All things considered, the day of the assault was set for Sunday, May 17. The assault took off at 6 a.m. and the attack was carried out at 8 a.m.

The entire plan was well thought out, and the targeted intensive training of the Combined Fleet had already begun as early as late August of the previous year. Yamamoto personally selected and appointed Mizuta Nakasa, a top pilot in the naval aviation corps with 3,000 hours of flight experience, as the chief instructor for training, responsible for the training of pilots. In view of the terrain characteristics of Pearl Harbor, where the water depth is only 10 to 12 meters, the torpedo pilots concentrated on Sakurajima in Kagoshima, where the terrain is similar to Pearl Harbor, and the height of the mine drop gradually decreased from 1,000 meters to 20 meters.

After approaching the harbor, the torpedo plane first lowered its altitude, zigzagged through the canyon at an altitude of 50 meters, lowered it to 20 meters as soon as it flew to the surface of the sea, and immediately fired a torpedo at the target. The entire attack maneuver was repeatedly rehearsed, and the essentials of the maneuver had been memorized by the pilots. The scientific research department of the Japanese army successfully developed the "Gai-2" type shallow water torpedo equipped with a wooden stabilizer, which solved the technical problem of using torpedoes in shallow water areas and ensured that the torpedo machine dropped a 60 percent hit rate at an altitude of 20 meters.

After two weeks of bombing by single planes and formations, the pilots hit 80 percent of their bombs, and the accuracy of hitting reached an extremely high level of 300 meters, with an altitude error of 30 meters. Technicians improved the bomb delivery device and converted 800 kg armor-piercing shells into aerial bombs to increase the power of the bombs.

Dive bomber and fighter pilots also underwent targeted training, all of which met the training requirements. In order to achieve better results in the air raids, all the pilots also intensified their training in identifying US warships. Since the aircraft carriers "Xianghe" and "Zuihe" of the Fifth Air Force were officially incorporated into the First Air Fleet in September last year, most of the pilots were transferred from the shore-based air force and were busy with intensive training for aircraft carriers to take off and landing, so they were unable to participate in the above-mentioned pre-war training. Therefore, Yamamoto decided that the 1st and 2nd Air Squadrons, which had undergone targeted training, would attack US ships, and the 5th Squadron would attack airfields.

At the same time, the participating ships also underwent intensive training. In order to adapt to the climatic characteristics of the northern route, surface warships focused on refueling training at sea in bad climates. The technicians have improved the refueling equipment and also analyzed and studied the refueling methods to help the ship units improve the efficiency of refueling at sea. Yamamoto was also concerned that if he could not get supplies from tankers, he made special preparations and training for refueling at sea from battleships and aircraft carriers to cruisers and destroyers as a backup. In addition, all large warships have streamlined unnecessary equipment and personal belongings, and all the saved deadweight has been loaded with fuel to increase fuel reserves.

The decision to use the pocket submarine was not decided until April 21, and the pocket submarine had to be equipped with an anti-submarine net cutting device and a self-detonation device, so the time was the most urgent, and the intense torpedo attack training was carried out in Midtown Bay, where the underwater terrain resembled Pearl Harbor, and finally the pocket submarine and the mother boat were hurriedly set off before they even had time to conduct joint training with the pocket submarine and the mother boat. The training of the above-mentioned units was carried out in extreme secrecy, and all the participants only knew the training requirements and did not know the purpose of the training at all.