From The Pacific War, Time-Life Books, 1986
...The First Battle of Tokyo Bay was now underway.
The Japanese Imperial Fleet was spread out, expecting to have time to form into battle formation before approaching Nimitz's main fleet. Unfortunately for them, deciphered communications alerted Nimitz to Yamamoto's approach.
At just before seven o'clock, American torpedo planes swooped down and knocked out the ailing cruiser Aoba, which had been heavily damaged in the Battle of Kagoshima Bay. The Japanese carriers were nearly up to a full complement of fighters- a number of Zeroes had been dispatched from the Japanese homeland and had rendezvoused with Yamamoto's fleet. However, they were still outnumbered by the American carrier-based fighters.
The American fighters slowly gave ground, as the Japanese laid down an oppressive sheet of anti-aircraft fire. Yamamoto pressed inexorably forward- he was determined to strike at the Americans while he still had his full strength. Despite the overwhelming superiority of American intelligence, Yamamoto was able to guess the formation of the American fleet and deployed his ships to their southwest in a wedge formation. The Imperial Fleet outnumbered Nimitz's surface fleet, except in one critical area- virtually all of Yamamoto's submarine escorts had been left behind, sacrificed to the need for a rapid attack. This emphasis on speed had indeed allowed Yamamoto to attack quickly, before American reinforcements could arrive. But it would prove to be a terrible mistake.
The Japanese fighter pilots performed with incredible skill, pushing back the American fighter screen and allowing the Japanese to close to within firing range of an isolated pocket of American escorts. Yamamoto drew up his ships in a firing line which devastated the outlying destroyers. Twenty American ships disappeared beneath the waves, carrying with them thousands of souls. At this time, about 7:45, the main American battle fleet arrived and a general melee resulted. The Japanese were firing at the limit of their range, but the Americans were still disorganized and unable to mount a full response. Yamamoto steamed his ships to the northeast, hoping to move around the Americans and rake them with a broadside again before they had even finished forming a battle line.
At this point, the Americans unleashed their secret weapon. A vast armada of submarines, some thirty squadrons, emerged almost simultaneously on the Japanese line's west and unleashed a huge wave of torpedoes before submerging again. The Japanese, arranged in firing line, were sitting ducks. Virtually every ship in the fleet was damaged, and many smaller ships were destroyed outright. The cruiser Chokai was the largest ship to go down in this attack.
Yamamoto, alarmed by this new threat, spread his ships further apart and detailed his remaining destroyer escorts to hunt the submarines down. The need to reorganize his fleet and to deal with the massive damage his fleet had taken stopped the assault on Nimitz's main fleet cold. Admiral Nimitz took full advantage of this respite and formed into a battle line, steaming to meet the head of the Japanese line. The first American shells fell, and the battlecruiser Haruna's rudder was crippled. On a collision course with the American line, the captain called on his men to stay at their posts. The Haruna continued firing despite a withering attack from all sides. At 8:03 am, the Haruna collided with the American battleship Arizona, whose engines had been disabled by earlier shellfire. While the Arizona sank, nearly all of its crew had had time to evacuate the ship.
Admiral Yamamoto cursed his fate. The American submarines were now dispersing and attacking from all angles. (Their torpedo fuses had been set to prevent detonation outside a certain range, to prevent damage to American ships, but one American destroyer was sunk by friendly torpedoes when it strayed into the kill zone.) At the same time, the Imperial Fleet's Zeroes were finally losing to the American fighters and Nimitz was pressing his attack on his line's northern end. Gritting his teeth, Yamamoto called for defensive manuevers, planning to withdraw the bulk of his fleet while his larger ships staged a rearguard defense.
This manuever failed. As the Japanese fleet began to gather again, the American submarines were able to send in torpedo after torpedo. A troop transport ship, out of control, collided with the battlecruiser Kongo, which began pouring oil into the ocean. An American fighter ignited the slick, and both Japanese ships exploded. As American fire began picking off the Japanese destroyer escorts, the submarines gathered on the eastern flank of the Japanese fleet, adding their torpedo fire to the maelstrom.
Finally, Admiral Yamamoto called a general retreat. Nimitz did not order his ships to pursue- he was concerned to maintain control over Tokyo Bay. However, he did instruct Admiral King's Second Fleet to block any attempt to retreat west that Admiral Yamamoto made.
The day's toll was grim. On the American side, three destroyer squadrons had been sent to the ocean floor, along with the Arizona and the carrier Enterprise, which had been punctured by shellfire in the engagement's early fighting. The Japanese, however, had their fleet gutted. Three battleships, the aircraft carriers Akagi and Soryu, nine cruisers, twelve squadrons of destroyers, and enough transports to move three full divisions- the Japanese had lost and lost heavily.
The First Battle of Tokyo Bay marked the beginning of the end for the Imperial Fleet. After the defeat, Yamamoto deduced correctly that his ciphers had been compromised. He adopted a tactic of dispersing his fleet in hopes of attacking stragglers. This might have been successful had the Americans not also adopted British radar technology. Time and again, a small task force of Japanese ships would find themselves confronted by an entire American fleet.
Between Tokyo Bay and January 25th, 1941, not a single American ship would be sunk by Japanese fire. The Japanese, however, steadily lost ground. Within two months, the largest navy on Earth would be reduced to a skeleton force of thirty-four ships, without destroyer escorts and nearly all in drydock for repairs.
The stage was set for the Pacific War's next phase.