Since the remaining planes of the Japanese army in Hawaii could not even protect Pearl Harbor, the US military could calmly support the ground forces with its powerful naval and air forces and easily capture the Japanese-occupied islands where the defenders were isolated and helpless, and annihilated more than 10,000 Japanese troops in less than half a month, while the US casualties were only more than 3,000.

However, the only remaining nail -- Oahu still has a complete Japanese field division and two independent garrisons, plus the Japanese officers and soldiers who have been evacuated from other islands one after another, and the soldiers recruited from the local Japanese population, the total strength is more than 50,000 men. In addition, Oahu has hundreds of remnants of Japanese aircraft and strong forts left behind by the American army, which is rarely strong.

Even so, after the Japanese refused to surrender, the U.S. forces launched a final assault on Oahu. Although the remnants of the Japanese planes on the island rose up to meet the battle, they would not have any suspense in the face of the US planes that were ten times more numerous than their own. After clearing the last vestige of the Japanese air power in Hawaii, the overwhelming fleet of American planes bombed all the uncovered military facilities on the island, especially the more than 100 B-29 strategic bombers from Liszynsky Island, which gave full play to their terrifying destructive power without fear for their own safety.

After just a few days, the only remaining defenses on Oahu were the fortified fortresses that the Americans had built with countless human and material resources. In order to reduce their own casualties, the American army once again sent an envoy to persuade the remnants of the Japanese army to surrender, but they were directly killed by the Japanese from afar, even if Nimitz knew that the enemy was deliberately trying to provoke him. He had to immediately order an attack on the coastal forts of Oahu

Since the fortress of Oahu was originally built by the Americans, Nimitz knew the power of its firepower all the time, with a total of 13 main batteries blocking all angles, and a 406mm cannon capable of inflicting deadly damage on any American warship, including the battleship Iowa. However, compared with the powerful naval artillery, Hawaii's anti-aircraft artillery had been damaged by the Japanese attack at the beginning, and later during the Japanese occupation, due to its lack of national strength, it has not been added to the level before the Pearl Harbor incident, and it has suffered heavy losses under the indiscriminate bombardment of the US army not long ago.

Therefore, Nimitz decided to give it a try by letting the strategic bombers of the Army Aviation carry special bombs first. Because I don't know the bottom of my heart. The US military directly chose the "Grand Slam" bomb, which was more powerful than the "goblet", but although one of the shots of this super bomb of more than 10 tons hit the top of a certain gun emplacement, it still failed to cause any substantial damage to it

"Tens of meters of soil, with two layers of armor plates and a solid layer of reinforced concrete, is really frustrating! This fort was once captured by the Japanese army. There used to be a lot of damage. It's so hard to bite. Wouldn't the other batteries be more difficult to deal with? Nimitz sighed helplessly, and could only let the bomber increase the height of the bomb. Even though he knew that doing so would greatly reduce the hit rate of the bomb, he had no better choice.

Luck psychology is really unacceptable, more than a dozen remaining "Grand Slams" finally hit the target, and the domestic reserves have been exhausted, do you have to wait for the domestic arsenal to be newly created? Speechless for a while, Nimitz couldn't help but complain about the original designers of the Oahu fortresses

In desperation, Nimitz had to order four Iowa-class battleships to fight, although it was very unwise for the battleships to bombard coastal fortresses of the same level, but the four Iowa-class battleships of the Pacific Fleet had a total of 36 406mm main guns, if the angle was chosen, they would only be threatened by the giant guns of the two batteries, and those two batteries were destroyed by the Japanese army, due to the lack of Japanese industrial base, the production capacity was greatly occupied by other arms projects, and there was not much spare power to reopen the production project of 406mm giant guns, In addition, the transportation distance is too long, so after repairing the turret, only one of the usable generals from the other turrets is used. In other words, there is only one 406mm cannon in the turret of those two batteries, and the US military has an eighteen-fold advantage in firepower, so it may not be impossible to fight. What's more, in history, even if a battleship loses a confrontation with a coastal fortress, it will rarely be sunk, and it is a big deal to drive back to the shipyard for repairs for a few months, as long as you can take Oahu as soon as possible, this price is still affordable.

However, compared to the fixed fortress guns, the stability of the hull was significantly worse, which inevitably seriously affected the hit rate of the shelling, especially the Iowa-class battleships because of their too slender hulls. What made the U.S. troops vomit blood even more was that the forts they built were extremely well defended, and the thick reinforced concrete and armor interlayers were almost impossible to penetrate, and only by accurately hitting the root of the barrel, or the shells drilled directly into the gap, or the exploding shrapnel damaged the barrel of the fortress guns and caused them to explode during the shelling, the two batteries could be solved, which was too difficult.

In the end, the U.S. military paid the heavy price of all four Iowa-class battleships being severely damaged, and one of them almost failed to reach the shipyard in time, and only destroyed a coastal battery, which caused the U.S. military to gnash their teeth. However, the other battery was finally overwhelmed after a long period of continuous use due to the old barrel, and by this time Nimitz almost wanted to give up the attack for the time being, and for a time the cheers of "God bless America" spread throughout the fleet, and the morale of the American army was quickly restored.

After the two batteries were resolved, the fire protection ring of the defenders' coastal guns was no longer complete, and the American ground troops could finally land relatively safely, and no matter how strong the defense of the Oahu fortress was, it would be much easier to attack from behind the batteries. However, the tenacity of the Japanese far exceeded the expectations of the Americans, not only did they fight to the last man, so that the Americans only captured a few dozen prisoners who were deeply unconscious, and each battery had personnel left in the ammunition depots to detonate them before they fell.

As a result, the U.S. military paid a high price of more than 50,000 dead and missing in order to retake Oahu, and all 13 artillery batteries that were vital to the defense system of Oahu were blown up by the Japanese, and the more important shipyards and docks were destroyed by the Japanese (to be continued......