On May 3rd 1942, the first day of the first modern naval engagement in history began, called the Battle of the Coral Sea. A Japanese invasion force succeeded in occupying Tulagi of the Solomon Islands in an expansion of Japan‘s defensive perimeter.
The United States, having broken Japan’s secret war code and forewarned of an impending invasion of Tulagi and Port Moresby, attempted to intercept the Japanese armada. Four days of battles between Japanese and American aircraft carriers resulted in 70 Japanese and 66 Americans warplanes destroyed.
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 – 41,826 long tons (42,497 t) – versus a light carrier, a destroyer, and several smaller warships – 19,000 long tons (19,000 t) – sunk by the Americans. Lexington represented, at that time, 25% of U.S. carrier strength in the Pacific. The Japanese public was informed of the victory with overstatement of the American damage and understatement of their own.
In strategic terms, however, 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.
This confrontation, called the Battle of the Coral Sea, marked the first air-naval battle in history, as none of the carriers fired at each other, allowing the planes taking off from their decks to do the battling. Among the casualties was the American carrier Lexington; “the Blue Ghost” (so-called because it was not camouflaged like other carriers) suffered such extensive aerial damage that it had to be sunk by its own crew. Two hundred sixteen Lexington crewmen died as a result of the Japanese aerial bombardment.
Prior to the Battle of the Coral Sea, General Douglas MacArthur had designated the Brisbane Line, allowing the Japanese to occupy the top half of Australia, in a line that started 60 miles north of Brisbane. MacArthur, who had previously evacuated from Manila to Brisbane when he lost the Philippines, also made plans to evacuate from Brisbane prior to the expected Japanese invasion of Australia.
Although Japan would go on to occupy all of the Solomon Islands, its victory was a Pyrrhic one: the cost of the Battle of the Coral Sea, in experienced pilots and aircraft carriers, was so great that Japan had to cancel its expedition to Port Moresby, Papua and other South Pacific targets, including Australia.