Imagine a volcanic island fortress bristling with anti-aircraft guns, its harbor teeming with warships, and its airfields churning out bombers. This wasn’t some dystopian fantasy; this was Rabaul, the impregnable stronghold Japan carved out in the South Pacific during World War II.
Rabaul’s strategic location made it a lynchpin in Japan’s Pacific ambitions. Nestled on the tip of New Britain, it controlled key shipping lanes and provided a springboard for offensives towards Australia and the Solomon Islands. The Japanese poured resources into fortifying Rabaul, constructing extensive tunnels, underground shelters, and airfields capable of launching hundreds of planes.
For a while, Rabaul lived up to its fearsome reputation. It withstood early Allied attacks and served as a vital staging ground for Japanese offensives. But as the tide of the war turned, Rabaul’s fate hung in the balance. The Allies, recognizing the fortress’s immense cost in blood and resources to capture directly, devised a daring strategy: bypass it!
Why was Rabaul so important to the Allies and the Japanese?
Rabaul was the capital of New Britain in the Solomon Islands chain in the Pacific. At the start of World War II, it was lightly defended by a small Australian garrison. Therefore, Rabaul fell rather quickly to a Japanese invasion force of 20,000 men on January 23, 1942.
Soon afterward, Rabaul became the primary strategic air and naval forces center for the Japanese in the South Pacific. As a result, it became a target for a planned allied invasion.
However, because of circumstances, the invasion of Rabaul never occurred. This was a decision that was to have a major effect on allied strategy in the Pacific, which resulted in a policy of “leapfrogging” around the Japanese. This policy would save many lives by avoiding major Japanese strong points, allowing them to wither on the vine.
The first American plans for an offensive against Rabaul began immediately after the Japanese defeat at Midway in June 1942.
General Douglas MacArthur proposed a quick campaign against Rabaul, which would result in the capture of that bastion in less than three weeks. Such an invasion would require a division of army troops in an amphibious assault. However, since this would also require two aircraft carriers, the navy objected because it would bring them into poorly charted waters within range of the Japanese warplanes based in Rabaul.
Because of these difficulties, the navy proposed a gradual approach to Rabaul by capturing enemy bases on the islands along the way. MacArthur agreed to this gradual approach with the planned invasion of Rabaul divided into three phases.
The first two phases involved the capture of the island of Tulagi and an advance along the northeast coast of New Guinea, simultaneous with an advance up the Solomon Islands. The third phase would be the actual assault on Rabaul itself.
By January 1943, as the Guadalcanal campaign was being concluded, it became apparent that the capture of Rabaul in the third phase would be much more difficult than originally planned. Representatives for Admiral Nimitz, Admiral William Halsey, and General MacArthur were sent to Washington, D.C., to work out plans for the invasion of Rabaul.
MacArthur’s representative, General Richard Sutherland, insisted that such an invasion would require, at a minimum, five extra divisions plus almost 2,000 planes. Such resources were not available, and the invasion of Rabaul was drastically modified with a much slower approach, including a landing on the side of New Britain opposite Rabaul.
This new, slower plan for the invasion of Rabaul came to be known as Operation Cartwheel.
Because of the vast resources necessary for an invasion of Rabaul, even on a slower timetable, the Joint Chiefs of Staff in Washington, D.C., in the summer of 1943, began to talk about bypassing Rabaul entirely. This idea of leapfrogging past Rabaul was strongly opposed by General MacArthur, who insisted that its capture was necessary to secure his right flank as he advanced toward the Philippines.
In December 1943, MacArthur had the 112th Cavalry Regiment land on Arawe on the opposite side of New Britain island from Rabaul. Ten days later, the First Marine Division landed 60 north of Arawe at Cape Gloucester.
Unfortunately, these troops soon got bogged down in the thick jungles of New Britain. The worst enemy of this campaign turned out to be Mother Nature, not the Japanese. By this time, however, Rabaul had been effectively neutralized by heavy allied bombardment, with over fifty ships and planes sent to the bottom of the harbor there. Because it no longer posed a threat and because of the extreme difficulty in capturing it, the Americans decided to bypass Rabaul entirely.
Although the Allied troops were spared the agony of an attempted capture of Rabaul, the fate of the Australian POWs captured in Rabaul in 1942 was quite gruesome. One hundred fifty prisoners were shot on the spot upon capture. Of the approximately 1400 other Australian prisoners remaining on Rabaul, only 400 would live until the end of the war. The rest died either due to starvation or by having their transport ship taking them to Japan torpedoed by an American submarine.
Although the Allies abandoned Rabaul as an objective, the Japanese continued to maintain their defenses of this bastion, thereby wasting much in terms of men and material. Meanwhile, the Americans used their experience of neutralizing Rabaul as the basis of their “leapfrog” tactics in the Pacific. They bypassed the Japanese strong points to attack more lightly defended islands. The criterion became not how many Japanese troops and armaments they could defeat or destroy but how to obtain islands to use as aerial launching points on the road to Japan with the least risk of casualties.
So strongly entrenched were the Japanese at Rabaul that after the war, it took nearly two years for all of their troops to be repatriated to their homeland. Had the allies chosen to attack Rabaul directly instead of wisely bypassing it, the result would have been many unnecessary casualties since the usefulness of Rabaul to the Japanese had ceased long before the war ended. In addition, the nearly 100,000 Japanese at Rabaul were enforced by tanks, artillery, and other supplies warehoused in underground bunkers.
Naval historian Samuel Eliot Morison put it best in his observation about the ultimate cost of assaulting Rabaul: “Tarawa, Iwo Jima, and Okinawa would have faded to pale pink in comparison with the blood which would have flowed if the Allies had attempted an assault on fortress Rabaul.”
Rabaul’s story is a testament to both the ingenuity of military strategy and the folly of overconfidence. It stands as a silent monument to the thousands of lives that could have been lost in a futile frontal attack, a stark reminder that sometimes, the greatest victories are won not by brute force, but by cunning and calculated risk.
