Battle of the Coral Sea — the first naval battle where the ships never saw each other.

In the first week of May 1942, two of the most powerful carrier forces ever assembled in the Pacific stalked each other through warm, rain-squalled waters north of the Coral Sea. For four days, the opposing admirals hurled reconnaissance aircraft into overcast skies, parsed fragmentary radio intercepts, and launched their attack groups toward targets they could not see. When the shooting stopped, the Battle of the Coral Sea had claimed two carriers, more than 1,400 lives, and hundreds of aircraft — and not a single surface ship from either fleet had come within visual range of the enemy. It was the first naval engagement in history fought entirely by aircraft, and it announced, with terrible clarity, that the age of the gun-line had ended.

The battle was the product of Japanese imperial ambition and a single strategic gamble designated Operation MO. By the spring of 1942, Japan's southern perimeter had expanded with startling speed — the Philippines, Malaya, the Dutch East Indies had all fallen — but Port Moresby, the vital Allied base on the southern coast of New Guinea, remained beyond reach. Its capture would put Japanese land-based bombers within range of northern Australia and sever the supply lines feeding MacArthur's forces. Vice Admiral Shigeyoshi Inoue assembled an amphibious force of some fifteen transports screened by cruisers and destroyers, with the light carrier Shōhō providing close air cover and two of the Imperial Navy's premier fleet carriers — Shōkaku and Zuikaku, veterans of the Pearl Harbor strike — assigned to neutralize any American response from open water.

The Americans were waiting. Through the extraordinary work of Navy codebreakers at Station HYPO in Pearl Harbor, Admiral Chester Nimitz had assembled Task Force 17 under Rear Admiral Frank Jack Fletcher, built around USS Yorktown (CV-5) and USS Lexington (CV-2). Lexington — "Lady Lex" to her 2,951 crew — was a behemoth: 36,000 tons of converted battlecruiser hull, capable of 33 knots and carrying more than 70 aircraft. The two task forces rendezvoused in the Coral Sea on May 1, their men largely unaware that the enemy carriers they hunted were led by officers who had personally planned the raid on Pearl Harbor just five months before. Rear Admiral Takeo Takagi commanded the Japanese carrier striking force; his air group chief, Rear Admiral Chuichi Hara, controlled the planes.

The first serious action, on May 7, illustrated how completely luck and misidentification governed this new kind of warfare. A Japanese scout plane reported two American vessels as "a carrier and a cruiser" and Hara launched a massive strike — 36 bombers, 24 torpedo planes — only to find the fleet oiler USS Neosho and her destroyer escort, USS Sims. Sims was sent to the bottom in minutes; Neosho, riddled and burning, drifted for four days before survivors were rescued. While the Japanese chased an oiler, American search aircraft found the light carrier Shōhō screening the invasion convoy north of the Louisiade Archipelago, and 93 aircraft descended on her in waves. Thirteen bombs and seven torpedoes struck home inside ten minutes. As Shōhō rolled and sank, Lieutenant Commander Robert Dixon radioed back to Yorktown one of the war's most famous dispatches: "Scratch one flattop."

May 8 brought the engagement that would define carrier warfare for the remainder of the war. Both sides launched their full strike groups simultaneously that morning — the Americans sending 84 aircraft southwest toward the Japanese carriers, the Japanese sending 69 planes northeast toward the American task force, the two formations passing within miles of each other in the low overcast without contact. The American strike found Shōkaku in open water; Zuikaku slipped into a convenient rain squall and survived unscathed, but three bomb hits tore open Shōkaku's flight deck forward and amidships, killed 109 men, and left her unable to launch aircraft. The Japanese strike, meanwhile, found Lexington and Yorktown — and what followed for Lady Lex was a slow maritime catastrophe that her crew could not stop.

Two Type 91 aerial torpedoes struck Lexington's port side within ninety seconds of each other, and two 250-kilogram bombs pierced her flight deck. Damage control crews fought brilliantly; within an hour, the fires were out, speed was restored to 25 knots, and her captain, Frederick Sherman, signaled the ship was fit for operation. Then, at 12:47 p.m., a spark ignited aviation gasoline vapors seeping from ruptured fuel lines deep in the hull. The explosion blew men off their feet from one end of the carrier to the other. A second explosion followed, then a third. By late afternoon the ship could not be saved; 2,735 survivors were evacuated to escorting cruisers and destroyers in good order, many men pausing to wash their hands before going over the side. The destroyer USS Phelps was ordered to finish her with torpedoes. Lexington slipped beneath the Coral Sea at 7:52 p.m. on May 8, 1942, carrying 216 of her crew with her.

The strategic consequences of the battle rippled far beyond the water where the ships went down. On paper, Japan had won: the Americans lost a fleet carrier to Japan's light carrier, and the tonnage math favored Tokyo. But Yorktown, damaged by a single bomb hit, limped to Pearl Harbor where damage assessors estimated three months of repairs. Nimitz gave the yard 72 hours. Working around the clock, some 1,400 workers patched her sufficiently to sortie, and Yorktown arrived at Midway in time to fight — and die — in the battle that broke the back of Japanese carrier aviation. More critically, Shōkaku's structural wounds and Zuikaku's catastrophic aircrew losses meant that neither fleet carrier was available for the Battle of Midway the following month. Inoue had already turned back his invasion convoy, unwilling to risk his transports without full air cover. Port Moresby was saved. The threat to Australia was broken. For the first time since Pearl Harbor, the Japanese advance had been stopped.

What the Battle of the Coral Sea established could not be undone. Admirals who had spent careers calculating gun ranges and armor thicknesses were now fighting enemies 175 miles away, at speeds measured in aircraft knots rather than ship knots, across horizons no lookout could see past. The battle had validated everything the carrier aviators of the 1930s had argued — at Naval Air Station North Island in San Diego, at Pensacola, in the prewar fleet exercises that senior admirals had largely dismissed — that the carrier was the new capital ship and aviation the primary arm of sea power. Many of the pilots who flew from Lexington and Yorktown that May had trained over San Diego Bay and the waters off Point Loma; some were among the American dead, and some came home to help build the Pacific Fleet that finished the war. The Coral Sea did not end the conflict — it barely slowed it. But it taught the admirals a new language for fighting at sea, one written entirely in aircraft and radio silence and the art of finding an enemy you would never see.