I’ve often heard of the Doolittle raiders, but how did that force the Japanese to change their strategy ?
More than anything I thought it was a psychological strike to show the Japanese people that they were vulnerable.
So, by mid-April 1942, the Japanese had been successful in overrunning French Indochina, Wake Island, the Philippines, the north coast of New Guinea, and the Dutch East Indies. The question was what to do next.
Understand something: the Japanese Army and the Japanese Navy hated each other so much that their relationship makes the OU-Texas game look like a love-in.
The Japanese Army wanted to expand its operations in China.
The Japanese Navy was split on what to do. The Navy General Staff wanted to expand the New Guinea campaign with an invasion of Port Moresby on the south coast. That would enable them to bomb and potentially invade Australia. Even if they never invaded Australia, they could make it untenable for use as a base from which the Allies could advance northward into the Greater East Asia Co-Prosperity Sphere.
But Admiral Yamamoto, architect of the Pearl Harbor raid, Commanding Officer of the Combined Fleet, believed that the navy's first priority needed to be the destruction of the U.S. carrier fleet. Yamamoto was so certain about this that he was implying that he would resign if he didn't get his way.
The Doolittle Raid took place in the middle of this debate. It
did shock and alarm the Japanese, especially as one of the B-25s dropped bombs within earshot of the Imperial Palace. It was obvious that the B-25s must have come from a carrier, odd as it seemed, because the Allies had no bases from which B-25s could reach Japan. So this strengthened Yamamoto's argument.
The Japanese Army and Navy did not agree on a combined effort. But within the Navy, Yamamoto's argument carried the day. Sort of.
The preparations for the operation to capture Port Moresby were too far advanced to easily cancel them. So a compromise was reached.
The Moresby operation (Operation MO) would go on as scheduled, in early May, but with reduced resources and a reduced objective. Then, in early June, Yamamoto would launch the Midway operation (Operation MI) to capture Midway Island in order to force to U.S. carriers to come out and fight, as Midway is too close to the main islands of Hawaii for the U.S. to allow Japan to hold it. When the U.S. carriers came out, the Japanese carriers would launch air strikes to destroy them. Oh, the Japanese would also launch an operation in the Aleutian Islands (Operation AL) to gain bases from which to threaten Alaska.
So, Operation MO went off, but our crypto guys in Hawaii figured out enough of it so that we had two task forces--built around the carriers USS
Yorktown and USS
Lexington--operating in the Coral Sea in position to attack the Moresby invasion fleet.
The ensuing Battle of the Coral Sea was the first naval battle in which the ships never spotted each other--it was all done by airplanes. It was a tactical victory for the Japanese, as we sank the light carrier
Shoho and damaged one of the two best fleet carriers in the world--
Shokaku--while we lost one of our two largest carriers--
Lexington--and got the somewhat smaller but more efficient fleet carrier
Yorktown damaged. Strategically, it was an Allied victory, as the Port Moresby invasion fleet was turned back. This was the first setback for the Japanese, although they chose not to recognize it as such. They counted ships and tonnage sunk and concluded that it had been a victory. There would be another time to come back and capture Port Moresby after they eliminated the U.S. carriers in Operation MI.
But
Shokaku--though not extensively damaged--would not even get into dry dock until after Operation MI. Just as bad--from the Japanese perspective--her sister ship
Zuikaku had taken serious losses to her air group. Japanese doctrine at the time considered the air group to be part of the ship's crew. Whereas the U.S. Navy would have taken an intact air group from a damaged ship and either replaced the shot-up air group or provided enough replacements to get it back up to full strength. But the Japanese didn't do it that way. So both
Shokaku and Zuikaku would be unavailable for Operation MI.
So the Japanese only had four carriers rather than six with which to attack Midway and then to destroy the U.S. carriers. They thought that that would be plenty. They figured that they had either sunk Yorktown or damaged her so badly that she would out of action for a long time at Coral Sea. In reality, Yorktown steamed back to Pearl Harbor right into dry dock and the workmen went right into action to repair her. They worked round the clock for the next 72 hours, whereupon
Yorktown--with her air group augmented by aircraft and crews from USS
Saratoga, Lexington's sister, who was on her way back to Pearl from a refit on the West Coast--steamed out with the escorts of her Task Force 17, and headed for a point NE of Midway, to join Task Force 16, with her two sister-ships,
Enterprise and
Hornet (who had not gotten back from the Doolittle Raid in time for the Coral Sea).
So, in carriers, the odds at Midway, in the first week of June, were 4-3 in favor of the Japanese, not 6-3, not 5-3, and not 4-2. And we got lucky. The Japanese conducted carrier strikes much better than we did, but we struck first, before they even knew that we had carriers in the vicinity of Midway. We sank or mortally wounded three Japanese carriers between 1020 and 1030 on 4 June 1942. The one Japanese carrier left,
Hiryu, hit
Yorktown twice, mortally wounding her, before strikes from
Yorktown and
Enterprise sank
Hiryu. (
Hornet's air group was pretty worthless at Midway. Just how worthless was covered up at the time and has only in recent years been fully understood.)
So, the Doolittle Raid caused Operation MO to be done half-assed, resulting in the temporary loss of the two best aircraft carriers in the world. This caused the Japanese carrier striking force to be at 2/3 strength for the Battle of Midway, which was an incredible victory for the Americans and a devastating defeat for the Japanese.
