"Communicate the attack targets to the Shiden unit again. The First Fleet is assigned to the center, the Second Fleet to the left flank, the Fourth Fleet to the right flank, and the Third Fleet to engage the enemy vanguard fleet."
Taking command of the first attack group and also entrusted with command in the second attack group, Lieutenant Commander Tomonaga gave concise and dispersed the 345 Shiden, each assigned to their designated targets. Each Shiden left one section of escort planes for each carrier, with the remaining aircraft carrying one 250 kg bomb on each wing, not for their primary combat role but as secondary bombers for this battle.
This measure is largely influenced by the discontinuation of the D3A dive bomber. The steep dive bombing, which penetrated to within a few hundred meters above enemy ships, had a high accuracy but also a high rate of being hit. As known since before the war, the D3A was equipped with considerable armor to counteract this. However, the anti-aircraft capabilities of the American ships far exceeded the expectations of the Imperial Navy, resulting in repeated losses of those dive bombers.
While the Imperial Navy was willing to accept some sacrifices for results, the attrition rate of the D3A was deemed unacceptable. As a result, they shifted their focus from dive bombing to high-speed, shallow-dive bombing that could pass over enemy ships without the need for dive brakes. Since this method could be carried out even by the Shiden and Tenzan, which lacked dive brakes, this change allowed them to equip 250 kg bombs on the hardpoints on both wings.
As the Shiden transitioned into an attacking formation, the American fleet had six battleships, ten cruisers, and fifty-two destroyers. Among them, half of the cruisers and destroyers had been damaged by the first attack group, significantly reducing their combat capabilities and mobility. The attackers' targets were these damaged cruisers and destroyers, regardless of whether they were damaged or intact. On the other hand, attacking battleships was strictly prohibited. While sinking the new battleship with bombs was not impossible, it would require a considerable number of accurate hits. Given the number of American ships, 345 attackers seemed rather inadequate. Therefore, the task of attacking the heavily armored new battleships was assigned to the powerful torpedoes, namely, the responsibility of the Tenzan.
The targeted American ships likely detected their movements in advance using radar. They interrupted rescue operations and entered evasive maneuvers as they saw fit. However, among them, there were clearly some ships not increasing their speed. Probably, they had experienced engine trouble due to the damage inflicted by the first attack squad, or there were issues with the hull or propulsion.
Nevertheless, the Shiden showed no mercy even to such ships. The 345 aircraft engaged in shallow-dive bombing against each cruiser or destroyer. The calculation was for ten to twelve 250 kg bombs to rain down on each ship. Despite the criticism of the inadequacy of the 250 kg bomb against battleships, except for certain exceptions like armored carriers, it could effectively damage all types of ships. The bombs, weighing more than twice the weight of heavy cruiser shells, could cause serious damage even with near misses, potentially delivering fatal blows to destroyers.
However, as mentioned earlier, the method of attack, being a shallow-dive bombing in all cases, results in a lower accuracy compared to the steep dive-bombing commonly used by the conventional D3A dive bombers. However, this comparison is with the steep dive bombing of the D3As, and the accuracy of the Shiden, piloted by skilled aviators, was by no means low. Additionally, the Imperial Navy, understanding the power aircraft possessed earlier than any other nation, made significant efforts to improve the performance of aiming devices for both gunfire and bombing.
The bombs dropped by the Shiden achieved a hit rate of at least ten percent, and under favorable conditions, it was not uncommon for the rate to exceed twenty percent. Probability-wise, the targeted ship would be hit by at least one bomb, and unlucky ones might endure two or more hits. In reality, all 62 American cruisers and destroyers were struck by direct hits or effective near misses from the 250 kg bombs. Some destroyers, unfortunate enough to be hit by multiple bombs, were already on the verge of sinking. Those that remained afloat were mostly moving forward with thick black smoke billowing and crawling.
At the end of the Shiden's attack, only six undamaged state-of-the-art battleships remained. With this, the anti-aircraft fire from the American fleet significantly diminished. The black smoke from the bursting high-caliber anti-aircraft shells covering the fleet overhead dissipated, and the number of machine gun and cannon rounds visibly decreased. The suspended rescue operations should have become extremely challenging. With all the nimble destroyers, capable of rescuing survivors, destroyed and preoccupied with their own survival, the situation became overwhelming. Moreover, many American soldiers and sailors likely perished in the aftermath of the underwater explosions of the off-target 250 kg bombs.
However, there were no kind of fools within the Imperial Navy's carrier-based air force silently watching the dire situation of the American fleet. Recognizing the vulnerability of the American cruisers and destroyers, 148 Tenzan attackers entered a coordinated strike to pierce the flanks of the remaining state-of-the-art battleships.