Darwin, Northern Territory, Australia · January 23, 1942

On this date in 1942, over a month after Pearl Harbor, 20,000 Japanese Marines quickly overran the Aus­tra­lian gar­ri­son at Rabaul, New Brit­ain, the largest is­land in the Bis­marck Archi­pel­ago (labeled “Niu Briten” on map below). Rabaul’s cap­ture was impor­tant because of its prox­im­ity to the Caro­line Islands to the north, site of a major Japa­nese naval base on Truk (known today as Chuuk). Soon after­wards Rabaul became the prin­ci­pal stra­tegic cen­ter for Japa­nese air and naval forces in the South­west Paci­fic. The island served as the key point for the failed Japa­nese invasion of Port Moresby (May–Novem­ber 1942), the capi­tal and largest popu­la­tion cen­ter of Papua New Guinea.

As the Allies wound down their Guadal­canal cam­paign (August 7, 1942, to Febru­ary 9, 1943), they recog­nized that recap­turing Rabaul, with its 100,000 ene­my soldiers and naval per­son­nel, rein­forced by 600 planes, tanks, artil­lery, and other sup­plies, would require more re­sources than they had at their com­mand—a min­i­mum of five extra divi­sions and almost 2,000 planes. How­ever, at the oppo­site (west­ern) end of the is­land, where the Japa­nese were in possession of two air­strips, U.S. Marine and Army units swarmed ashore to cap­ture the air­fields they believed would assist them in their planned attack on the Rabaul strong­hold.

The Battle of Cape Glouces­ter (Decem­ber 26, 1943, to April 22, 1944), part of Oper­a­tion Cart­wheel, a mixed land, sea, and air operation in the Southwest Pacific (1943–1944), was said by vete­rans to have been “worse than Guadal­canal.” The troops got bogged down in swampy terrain and thick jungle, where the chief enemy was Mother Nature. By this time, how­ever, Rabaul had been effec­tively neu­tral­ized by heavy Allied bom­bard­ment, with over fifty Japa­nese ships and planes sent to the bottom of the harbor there. Because it no longer posed a threat and because of the per­ceived diffi­cul­ty in cap­turing it, war planners wisely decided to “island hop” past Rabaul to attack more lightly defended islands, sparing them­selves another Iwo Jima or Oki­nawa. So impreg­nable were the Japa­nese at Rabaul that it took nearly two years to evacuate all their troops after the war.

Battle of Cape Gloucester, December 26, 1943, to April 22, 1944

Bismarck Archipelago, Southwest Pacific

Above: Location of Rabaul and the island of New Britain (“Niu Briten”) in the Bis­marck Archi­pelago, South­west Pacific. Cape Glouces­ter (also known as Tuluvu), which is on the western tip of New Britain, does not appear on this map.

1st Marine Division at Cape Gloucester, December 1943Cape Gloucester landings, December 1943

Left: Men and cargo of the 1st Marine Division, veterans of the campaign on Guadalcanal (August 7, 1942, to Febru­ary 9, 1943), are pictured aboard a landing craft for the invasion of Cape Glouces­ter, December 1943. Cape Glouces­ter was located on the northern side of the far west of the island of New Britain.

Right: The initial landings at Cape Gloucester had as their main objec­tive the iso­la­tion of Rabaul, 300 miles to the east on the other side of the island. The plan called for the Allies to secure Cape Glouces­ter’s beach­heads and capture the dual airfields to assist in planned attacks on the Japa­nese garri­son at Rabaul. The Marines took the air­fields on Decem­ber 30, 1943, after slogging for three days through neck-deep swamps (marked “Damp Flats” on their maps), where men were actually killed by sodden branches falling from rotting trees. Impeded by heavy rains, Army avia­tion engi­neers worked around the clock to make Air­field No. 2, the larger of the air­strips, operational, a task that took them until the end of January 1944. In the end the two airstrips proved of marginal value to the Allies.

New Britain jungle landscapeMarines’ machine gun nest, Cape Gloucester

Above: Embattled Marines at times could see no more than a few feet ahead of them owing to the thick jungle (left frame). Retreating at first into the jungle of Cape Glouces­ter, Japa­nese soldiers finally gathered strength and counter­attacked their Marine pur­suers. The photo in the right frame shows Marines in the forest’s darkness fending off a Japa­nese attack using an M1917 Browning machine gun. Marines needed three weeks of hand-to-hand combat to clear more than 10,000 enemy troops from the imme­diate area around Cape Glouces­ter. The Cape Glouces­ter base effectively bottled up the 135,000 Japa­nese troops at Rabaul, because the dense, jungle-swathed mountain ridges of the interior were impassable.

Marines try erecting a tent at Cape Gloucester base camp during a monsoon delugeCape Gloucester’s thick jungle made vehicular traffic almost impossible

Left: Atrocious weather in the “green inferno” of New Britain proved to be the main problem for Marines and soldiers at Cape Glouces­ter. Monsoon deluges—as much as 16 inches of rain fell in a day—flooded fox­holes and made life miser­able in the base camp. Wet uni­forms never really dried, and the men suffered contin­ually from fungus infec­tions, the so-called jungle rot, which readily developed into open sores. Mosquito-borne malaria threatened the health of the men, who also had to contend with other insects—“little black ants, little red ants, big red ants” on an island where “even the caterpillars bite.”

Right: Move­ment on foot or by vehicle through the island’s swamp, jungles, and tall, coarse kunai grass verged on the impos­sible, espe­cially where mon­soon rains had flooded the land or turned the volcanic soil into slippery mud.

“Rings Around Rabaul.” Victory at Sea Episode Makes Excellent Use of Japanese and American Footage