The Battle of the Coral Sea, fought from 4 to 8 May 1942, was a major naval battle between the Imperial Japanese Navy (IJN) and naval and air forces from the United States and Australia, taking place in the Pacific Theatre of the Second World War. The battle is historically significant as the first action in which aircraft carriers engaged each other, as well as the first in which neither side's ships sighted or fired directly upon the other.

In an attempt to strengthen its defensive position in the South Pacific, Japan decided to invade and occupy Port Moresby (in New Guinea) and Tulagi (in the southeastern Solomon Islands). The plan to accomplish this was called Operation MO, and involved several major units of Japan's Combined Fleet. These included two fleet carriers and a light carrier to provide air cover for the invasion forces. It was under the overall command of Japanese Admiral Shigeyoshi Inoue.

The U.S. learned of the Japanese plan through signals intelligence, and sent two United States Navy carrier task forces and a joint Australian-American cruiser force to oppose the offensive. These were under the overall command of American Admiral Frank J. Fletcher.

Naval tacticsEdit

The battle was the first naval engagement in history in which the participating ships never sighted or fired directly at each other. Instead, manned aircraft acted as the offensive artillery for the ships involved. Thus, the respective commanders were participating in a new type of warfare, carrier-versus-carrier, with which neither had any experience. In H. P. Willmot's words, the commanders "had to contend with uncertain and poor communications in situations in which the area of battle had grown far beyond that prescribed by past experience but in which speeds had increased to an even greater extent, thereby compressing decision-making time."[1] Because of the greater speed with which decisions were required, the Japanese were at a disadvantage as Inoue was too far away at Rabaul to effectively direct his naval forces in real time, in contrast to Fletcher who was on-scene with his carriers. The Japanese admirals involved were often slow to communicate important information to one another.[2]

The experienced Japanese carrier aircrews performed better than those of the U.S., achieving greater results with an equivalent number of aircraft. The Japanese attack on the American carriers on 8 May was better coordinated than the U.S. attack on the Japanese carriers. The Japanese suffered much higher losses to their carrier aircrews, losing ninety aircrew killed in the battle compared with thirty-five for the Americans. Japan's cadre of highly skilled carrier aircrews with which it began the war were, in effect, irreplaceable because of an institutionalised limitation in its training programs and the absence of a pool of experienced reserves or advanced training programs for new airmen. Coral Sea started a trend which resulted in the irreparable attrition of Japan's veteran carrier aircrews by the end of October 1942.[3]

The Americans did not perform as expected, but they learned from their mistakes in the battle and made improvements to their carrier tactics and equipment, including fighter tactics, strike coordination, torpedo bombers and defensive strategies, such as anti-aircraft artillery, which contributed to better results in later battles. Radar gave the Americans a limited advantage in this battle, but its value to the U.S. Navy increased over time as the technology improved and the Allies learned how to employ it more effectively. Following the loss of Lexington, improved methods for containing aviation fuel and better damage control procedures were implemented by the Americans.[4] Coordination between the Allied land-based air forces and the U.S. Navy was poor during this battle, but this too would improve over time.[5]

Japanese and U.S. carriers faced off against each other again in the battles of Midway, the Eastern Solomons, and the Santa Cruz Islands in 1942, and the Philippine Sea in 1944. Each of these battles was strategically significant, to varying degrees, in deciding the course and ultimate outcome of the Pacific War.[6]


Both sides publicly claimed victory after the battle. In terms of ships lost, the Japanese won a tactical victory by sinking an American fleet carrier, an oiler, and a destroyer – Template:Convert/LT – versus a light carrier, a destroyer, and several smaller warships – Template:Convert/LT – sunk by the Americans. Lexington represented, at that time, 25% of U.S. carrier strength in the Pacific.[7] The Japanese public was informed of the victory with overstatement of the American damage and understatement of their own.[8]

In strategic terms, the Allies won because the seaborne invasion of Port Moresby was averted, lessening the threat to the supply lines between the U.S. and Australia. Although the withdrawal of Yorktown from the Coral Sea conceded the field, the Japanese were forced to abandon the operation that had initiated the Battle of Coral Sea in the first place.[9]

The battle marked the first time that a Japanese invasion force was turned back without achieving its objective, which greatly lifted the morale of the Allies after a series of defeats by the Japanese during the initial six months of the Pacific Theatre. Port Moresby was vital to Allied strategy and its garrison could well have been overwhelmed by the experienced Japanese invasion troops. The U.S. Navy also exaggerated the damage it inflicted,[10] which was to cause the press to treat its reports of Midway with more caution.[11]

The results of the battle had a substantial effect on the strategic planning of both sides. Without a hold in New Guinea, the subsequent Allied advance, arduous though it was, would have been more difficult.[12] For the Japanese, who focused on the tactical results, the battle was seen as merely a temporary setback. The results of the battle confirmed the low opinion held by the Japanese of American fighting capability and supported their overconfident belief that future carrier operations against the U.S. were assured of success.[13]


  1. Willmott 2002, pp. 37–38
  2. Willmott (2002), pp. 37–38; Millot, pp. 114 & 117–118; Dull, p. 135; Lundstrom (2006), p. 135; D'Albas, p. 101; Ito, p. 48; Morison, pp. 63–64.
  3. Wilmott (1983), pp. 286–287 & 515; Millot, pp. 109–111 & 160; Cressman, pp. 118–119; Dull, p. 135; Stille, pp. 74–76; Peattie, pp. 174–175.
  4. ONI, pp. 46–47; Millot, pp. 113–115 & 118; Dull, p. 135; Stille, pp. 48–51; Parshall, p. 407. A Yorktown crewman, Machinist Oscar W. Myers, noted that an aviation gasoline fire on the hangar deck contributed to Lexington's demise. Myers developed a solution, soon implemented in all US carriers, of draining the fuel pipes after use and filling the pipes with carbon dioxide to prevent such fires from taking place again (Parshall, p. 407).
  5. Crave, p. 451; Gillison, pp. 523–524. According to Gillison, the poor coordination between Fletcher and MacArthur contributed to the friendly fire incident against Crace on 7 May.
  6. D'Albas, p. 102; Stille, pp. 4–5 & 72–78. The US Navy later named a Midway-class aircraft carrier Template:USS after the battle.
  7. Millot, pp. 109–11; Dull, pp. 134–5; Lundstrom (2006), p. 203; D'Albas, p. 109; Stille, p. 72; Morison, p. 63. The Japanese thought they sank LexingtonTemplate:'s sister ship, Template:USS.
  8. Edwin P. Hoyt, Japan's War, pp. 283–4 ISBN 0-07-030612-5
  9. Wilmott (1983), pp. 286–7 & 515; Millot, pp. 109–11 & 160; Lundstrom (2006), p. 203; D'Albas, p. 109; Stille, p. 72; Morison, p. 63.
  10. William L. O'Neill, A Democracy At War: America's Fight At Home and Abroad in World War II, p. 119 ISBN 0-02-923678-9
  11. William L. O'Neill, A Democracy At War: America's Fight At Home and Abroad in World War II, p. 125 ISBN 0-02-923678-9
  12. Lundstrom (2006), p. 203; D'Albas, p. 109; Stille, p. 72; Morison, p. 64.
  13. Willmott 1983, p. 118
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