2-4 Mar 1943
While the Guadalcanal campaign was raging, an equally bitter series of battles was occurring on the island of New Guinea. Under the direction of Japanese war minister Hajime Sugiyama, Japanese troops were sent to seize an airfield near Wau, thirty-two miles from Salamaua. MacArthur's forces were ready for them, routing the Japanese invaders with an Australian brigade. Then Imperial General Headquarters ordered a convoy from Rabaul to land much-needed reinforcements in the Buna-Gona area under the code name of Operation 81. The convoy was consisted of six transports, one old navy supply ship, and one small freighter (carrying a total of 6,600 troops) and was escorted by eight destroyers. The convoy set sail riding on the front of heavy weather to hide their movement, but it was nevertheless discovered hours after their departure from Rabaul, New Britain on 1 Mar 1943. Attacks launched on the same day failed to locate the convoy, but in the following two days the Japanese ships were utterly overwhelmed by Allied air power, leading to the sinking of all eight transport ships and four of the eight destroyers by strafing, bombing, and skip-bombing; additionally, eight Zero fighters and seven Ki-43 fighters were shot down.
The aftermath of the battle was ugly for both sides. On 3 Mar 1943, after shooting down US B-17 bomber "Double Trouble", Japanese fighters strafed at the descending parachutes in frustration. Having observed this act, the Americans lowered themselves to the same level during the subsequent attack waves in which they not only dropped bombs on rescuing barges but also machine gunned survivors floating in the water. These attacks on the helpless Japanese survivors would continue through 5 Mar 1943.
After the Battle of the Bismarck Sea, in which the Japanese suffered more than 3,000 killed, the Japanese would never again attempt to run slow transports into the face of American air power.
When Kenney woke MacArthur to inform him the news of the victory at Bismarck Sea, Kenney commented that "I had never seen him so jubilant". MacArthur, at a press conference that soon followed the Bismarck Sea action, declared that the control of the sea "no longer depends solely or even primarily upon naval power, but upon air power operating from land bases held by ground troops". This offended members of the US Navy, but even the admirals could not deny that airpower was a decisive factor in the Pacific War.