Battle of Midway
June 4, 2006 | Leave a Comment
The Battle of Midway, fought near the Central Pacific island of Midway, is considered the decisive battle of the war in the Pacific. Before this battle the Japanese were on the offensive, capturing territory throughout Asia and the Pacific. By their attack, the Japanese had planned to capture Midway to use as an advance base, as well as to entrap and destroy the U.S. Pacific Fleet. Because of communication intelligence successes, the U.S. Pacific Fleet surprised the Japanese forces, sinking the four Japanese carriers, that had attacked Pearl Harbor only six months before, while only losing of one carrier. After Midway, the Americans and their Allies took the offensive in the Pacific.
Following the outbreak of the Pacific War in December 1941, the Japanese armed forces conducted military operations against U.S., British Commonwealth, and Dutch possessions in the Pacific and Southeast Asia. The first phase of these operations, which was the seizure of Malaysia, Singapore, the Dutch East Indies, the Philippines, and various island groups in the central and western Pacific, was virtually complete by March 1942. The second phase, initiated by Japanese Imperial Headquarters on 23 January, was designed to isolate and neutralize Australia and India. In the Pacific, this plan envisioned the seizure of bases in Papua/New Guinea and the Solomon Islands, which would be used to support future operations against New Caledonia, Fiji, and Samoa. By early March, with the seizure of Lae and Salamaua, the entire north coast of Papua/New Guinea had fallen to Japanese forces who were planning for an amphibious invasion of Port Moresby.
By this time, two secure American naval intelligence centers were in operation in the Pacific: one in Melbourne, Australia, and another at Pearl Harbor (“Hypo”). A third, at Corregidor (“Cast”), was rapidly disintegrating under Japanese air and artillery attacks on the island. Its cryptanalysts and equipment were in the process of evacuation to Melbourne. These facilities intercepted Japanese radio communications and, through traffic analysis and codebreaking, uncovered the location of major fleet units and shore based air forces. More importantly, by translating messages and studying operational patterns, Melbourne and Hypo predicted future Japanese operations. The intelligence centers provided their analysis, through daily communications intelligence (COMINT) briefings and warning reports, to senior American commanders, including Commander in Chief, U.S. Fleet (Admiral Ernest J. King), and Commander in Chief, Pacific Fleet (Admiral Chester W. Nimitz).
In early March, the Japanese postponed their planned seizure of Port Moresby because of previous events. An American carrier raid on Japanese shipping at Lae and Salamaua on the 10th, along with a previously unsuccessful attempt to attack Rabaul on 20 February, had demonstrated to Commander in Chief, Fourth Fleet (Admiral Shigeyoshi Inouye), that Japanese were not assured of air superiority in the region. It was not until early May, when Admiral Inouye had three carriers for operations, that the invasion could begin. On 7-8 May, the first carrier battle of the war took place in the Coral Sea. Each side had a carrier damaged, while the American lost the carrier USS Lexington and the Japanese lost the light carrier Shoho. More important the Japanese broke off their invasion attempt. It was the first time the Japanese had been stopped in the Pacific. Significantly, American cryptanalysts had provided crucial order of battle and operational communications intelligence to the Allied commanders in the South Pacific.
In addition to this advance toward Port Moresby, evidence that Japan was intent on expanding east of the Marshall Islands appeared in COMINT in early 1942. Land-based air units and equipment began appearing in message traffic to and from the Marshall Islands and the Mandates. On 4 March, the designator “AF” began appearing in partially decoded messages. Then, on 5 March, Japanese seaplanes, refueled from a submarine at French Frigate Shoals, Territory of Hawaii, conduct a small armed reconnaissance mission over Oahu. Finally, on 13 March, American cryptanalysts both broke the Japanese Navy’s General-Purpose Code (JN 25) and identified “AF” as Midway Island.
On 16 April, after several months of discussion, Commander in Chief, Combined Fleet (Admiral Isoruku Yamamoto), convinced the Imperial General Staff to agree to his Midway and Aleutians strategy for the summer. In Admiral Yamamoto’s view, the capture of Midway Island would allow Japan to pursue its Asian policies behind an impregnable eastern shield of defenses in the Central Pacific. The centerpiece of this plan was a feint toward Alaska followed by an invasion of Midway. When the U.S. Pacific Fleet responded to the landings on Midway, Japanese carrier and battleship task forces, waiting unseen to the west of the Midway strike Force, would fall upon and destroy the unsuspecting Americans. If successful, the plan would effectively eliminate the U.S. Pacific Fleet for at least a year and provide a forward outpost from which ample warning of any future threat by the U.S. would come.
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