By spring of 1942, the Japanese controlled all the tinted areas indicated on this map of the Pacific Ocean.  The General Staff of the Japanese Navy developed a plan to isolate Australia in order to prevent it from becoming a base for the expected American counter-offensive.  The first step was for the Japanese to occupy Tulagi in the Solomons and Port Moresby in New Guinea. The invasion forces were to be protected by the small-carrier Shoho and large-carriers Shokaku and Zuikaku.

3 May 1942

Yorktown and Lexington were sent to the Coral Sea to counter Japanese operations; however, Admiral Fletcher was tanking his task force 500 miles south of  the Solomons when the Tulagi invasion occurred. The landings at Tulagi proceeded unopposed

4 May 1942

Yorktown, hidden by a 100-mile-wide cold front, proceeded to a point within 20 miles of Tulagi.  TBD Devastator torpedo planes and SBD Dauntless dive-bombers launched strikes against the Japanese at Tulagi.  F-4F Wildcat fighters were used for combat air patrol. The Japanese large-carriers were too far to the north to provide support for their forces at Tulagi.

7 May 1942

The oiler Neosho and destroyer Sims were detached from Fletcher’s task force on May 6^th and mistakenly reported as a carrier and a cruiser by Japanese scout planes on May 7^th. The Japanese large-carrier group launched 78 aircraft against the misidentified oiler and destroyer. The Zeke fighters, Val dive-bombers and Kate Torpedo-aircraft blew the Sims out of the water and disabled the Neosho, which sank four days later.

Meanwhile, Fletcher’s scout aircraft misreported two cruisers to the north as two carriers, causing Fletcher to launch his strike aircraft in a direction opposite the Japanese’s large-carrier task force. Fortunately, the Shoho was sighted by a scout aircraft that was part of Commander W.B. Ault’s SBD Lexington attack group.  Ninety-three Lexington and Yorktown aircraft overwhelmed the small-carrier’s defenses.  Shoho sank five minutes after the attack ended, allowing the second SBD leader, Lieutenant Commander Dixon,  to utter the immortal phrase, “Scratch one flattop! Dixon to Carrier, Scratch one flattop!”

8 May 1942

Strike groups from the opposing task forces passed each other on opposite headings without visual contact. Yorktown and Lexington aircraft struck first.  The Japanese carriers were in rain squalls in the northern cold front, making discovery and coordinated attack difficult.  While the Zuikaku was hiding in a rain squall,  Yorktown aircraft put two bombs on the Shokaku.  Lexington aircraft added one more.  

Japanese torpedo-aircraft and dive-bombers conducted their attacks on the US carriers. The US carriers were in the clear to the south. Two bombs hit the Yorktown, resulting in minor damage.  Two torpedoes and three bombs hit the Lexington; however, she was still capable of recovering aircraft.  Unfortunately, an internal explosion doomed the Lady Lex. She was abandoned, then sunk by US destroyers.

The first major naval engagement in which the opposing ships never came within sight of each ended in tactical victory for the Japanese and strategic victory for the US. The US lost more tonnage. However, the Japanese, Port Moresby invasion force was turned back.  In addition, The Shokaku was seriously damaged and the Zuikaku’s air group depleted, resulting in both large-carriers missing the Battle of Midway