Battle of the Bismarck Sea The Battle of the Bismarck Sea ( 2 – 4 March 1943 ) took place in the South West Pacific Area ( SWPA ) during World War II . Over the course of the battle , aircraft of the U . S . Fifth Air Force and the Royal Australian Air Force ( RAAF ) attacked a Japanese convoy that was carrying troops to Lae , New Guinea . Most of the task force was destroyed , and Japanese troop losses were heavy . The Japanese convoy was a result of a Japanese Imperial General Headquarters decision in December 1942 to reinforce their position in the South West Pacific . A plan was devised to move some 6 , 900 troops from Rabaul directly to Lae . The plan was understood to be risky , because Allied air power in the area was strong , but it was decided to proceed because otherwise the troops would have to march through inhospitable swamp , mountain and jungle terrain without roads . On 28 February 1943 , the convoy – comprising eight destroyer s and eight troop transport s with an escort of approximately 100 fighter s – set out from Simpson Harbour in Rabaul . The Allies had detected preparations for the convoy , and naval codebreakers in Melbourne ( FRUMEL ) and Washington , D . C . , had decrypted and translated messages indicating the convoy ’ s intended destination and date of arrival . The Allied Air Forces had developed new techniques they hoped would improve the chances of successful air attack on ships . They detected and shadowed the convoy , which came under sustained air attack on 2 – 3 March 1943 . Follow - up attacks by PT boat s and aircraft were made on 4 March . All eight transports and four of the escorting destroyers were sunk . Out of 6 , 900 troops who were badly needed in New Guinea , only about 1 , 200 made it to Lae . Another 2 , 700 were rescued by destroyers and submarines and returned to Rabaul . The Japanese made no further attempts to reinforce Lae by ship , greatly hindering their ultimately unsuccessful efforts to stop Allied offensives in New Guinea . Background . Allied offensives . Six months after Imperial Japan attacked Pearl Harbor in December 1941 , the United States won a strategic victory at the Battle of Midway . Seizing the strategic initiative , the United States and its Allies landed on Guadalcanal in the southern Solomon Islands in August 1942 , beginning the Solomon Islands Campaign . The battle for Guadalcanal ended in victory for the Allies with the withdrawal of Japanese forces from the island in early February 1943 . At the same time , Australian and American forces in New Guinea repulsed the Japanese land offensive along the Kokoda Track . Going on the offensive , the Allied forces captured Buna – Gona , destroying Japanese forces in that area . The ultimate goal of the Allied counter - offensives in New Guinea and the Solomons was to capture the main Japanese base at Rabaul on New Britain , later codified as Operation Cartwheel , and clear the way for the eventual reconquest of the Philippines . Recognising the threat , the Japanese continued to send land , naval , and aerial reinforcements to the area in an attempt to check the Allied advances . Japanese plans . Reviewing the progress of the Battle of Guadalcanal and the Battle of Buna – Gona in December 1942 , the Japanese faced the prospect that neither could be held . Accordingly , Imperial General Headquarters decided to take steps to strengthen the Japanese position in the South West Pacific by sending Lieutenant General Jusei Aoki ’ s 20th Division from Korea to Guadalcanal and Lieutenant General Heisuke Abe ’ s 41st Division from China to Rabaul . Lieutenant General Hitoshi Imamura , the commander of the Japanese Eighth Area Army at Rabaul , ordered Lieutenant General Hatazō Adachi ’ s XVIII Army to secure Madang , Wewak and Tuluvu in New Guinea . On 29 December , Adachi ordered the 102nd Infantry Regiment and other units under the command of Major General Toru Okabe , the commander of the infantry group of the 51st Division , to move from Rabaul to Lae and advance inland to capture Wau . Following the decision to evacuate Guadalcanal on 4 January , the Japanese switched priorities from the Solomon Islands to New Guinea , and it was decided to send the 20th and 41st Divisions to Wewak . On 5 January 1943 , the convoy which consisted of five destroyers and five troop transports carrying Okabe ’ s force set out for Lae from Rabaul . Forewarned by Ultra , United States Army Air Forces ( USAAF ) and Royal Australian Air Force ( RAAF ) aircraft spotted , shadowed and attacked the convoy , which was shielded by low clouds and Japanese fighters . The Allies claimed to have shot down 69 Japanese aircraft for the loss of 10 of their own . An RAAF Consolidated PBY Catalina sank the transport . Although destroyers rescued 739 of the 1 , 100 troops on board , the ship took with it all of Okabe ’ s medical supplies . Another transport , , was so badly damaged at Lae by USAAF North American B - 25 Mitchell s that it had to be beached . Nonetheless , the convoy succeeded in reaching Lae on 7 January and landing its troops , but Okabe was defeated in the Battle of Wau . Most of the 20th Division was landed at Wewak from naval high speed transports on 19 January 1943 . The bulk of the 41st Division followed on 12 February . Imamura and Vice Admiral Gunichi Mikawa , the commander of the South East Area Fleet , developed a plan to move the command post of the headquarters of the Japanese XVIII Army and the main body of the 51st Division from Rabaul to Lae on 3 March , followed by moving the remainder of the 20th Division to Madang on 10 March . This plan was acknowledged to be risky because Allied air power in the area was strong . The XVIII Army staff held war games that predicted losses of four out of ten transports , and between 30 and 40 aircraft . They gave the operation only a 50 – 50 chance of success . On the other hand , if the troops were landed at Madang , they faced a march of more than over inhospitable swamp , mountain and jungle terrain without roads . To augment the three naval and two army fighter group s in the area assigned to protect the convoy , the Imperial Japanese Navy temporarily detached 18 fighters from the aircraft carrier " Zuihō ’ s " fighter group from Truk to Kavieng . Allied intelligence . The Allies soon began detecting signs of preparations for a new convoy . A Japanese floatplane of the type normally used for anti - submarine patrol s in advance of convoys was sighted on 7 February 1943 . The Allied Air Forces South West Pacific Area commander – Lieutenant General George Kenney – ordered an increase in reconnaissance patrols over Rabaul . On 14 February , aerial photographs were taken that showed 79 vessels in port , including 45 merchant ships and six transports . It was clear that another convoy was being prepared , but its destination was unknown . On 16 February , naval codebreakers in Melbourne ( FRUMEL ) and Washington , D . C . finished decrypting and translating a coded message revealing the Japanese intention to land convoys at Wewak , Madang and Lae . Subsequently , codebreakers decrypted a message from the Japanese 11th Air Fleet to the effect that destroyers and six transports would reach Lae about 5 March . Another report indicated that they would reach Lae by 12 March . On 22 February , reconnaissance aircraft reported 59 merchant vessels in the harbour at Rabaul . Kenney read this Ultra intelligence in the office of the Supreme Allied Commander , South West Pacific Area – General Douglas MacArthur – on 25 February . The prospect of an additional 6 , 900 Japanese troops in the Lae area greatly disturbed MacArthur , as they might seriously impact on his plans to capture and develop the area . Kenney wrote out orders , which were sent by courier , for Brigadier General Ennis Whitehead , the deputy commander of the Fifth Air Force , and the commander of its Advance Echelon ( ADVON ) in New Guinea . Under the Fifth Air Force ’ s unusual command arrangements , Whitehead controlled the Allied Air Forces units of all types in New Guinea . This included the RAAF units there , which were grouped as No . 9 Operational Group RAAF , under the command of Air Commodore Joe Hewitt . Kenney informed Whitehead of the proposed convoy date , and warned him about the usual Japanese pre - convoy air attack . He also urged that flying hours be cut back so as to allow for a large strike on the convoy , and instructed him to move forward as many aircraft as possible so that they could be close to the nearby captured airfields around Dobodura , where they would not be subject to the vagaries of weather over the Owen Stanley Range . Kenney flew up to Port Moresby on 26 February , where he met with Whitehead . The two generals inspected fighter and bomber units in the area , and agreed to attack the Japanese convoy in the Vitiaz Strait . Kenney returned to Brisbane on 28 February . Allied tactics . In the South West Pacific , a conventional strategic bombing campaign was out of the question , as industrial targets in Japan were well beyond the range of even the largest strategic bombers operating from bases in Australia and New Guinea . Therefore the primary mission of the Allied bomber force was interdiction of Japanese supply lines , especially the sea lanes . The results of the effort against the Japanese convoy in January were very disappointing ; some 416 sorties had been flown with only two ships sunk and three damaged , so clearly , a change of tactics was in order . Group Captain Bill Garing , an RAAF officer on Kenney ’ s staff with considerable experience in air - sea operations , including a tour of duty in Europe , recommended that Japanese convoys be subjected to simultaneous attack from different altitudes and directions . Major Paul I . " Pappy " Gunn and his men at the 81st Depot Repair Squadron in Townsville , Queensland , modified some USAAF Douglas A - 20 Havoc light bombers by installing four machine gun s in their noses in September 1942 . Two fuel tanks were added , giving the aircraft more range . An attempt was then made in December 1942 to create a longer range attack aircraft by doing the same thing to a B - 25 medium bomber to convert it to a " commerce destroyer " , but this proved to be somewhat more difficult . The resulting aircraft was nose heavy despite added lead ballast in the tail , and the vibrations caused by firing the machine guns were enough to make rivets pop out of the skin of the aircraft . The tail guns and belly turrets were removed , the latter being of little use if the aircraft was flying low . The new tactic of having the B - 25 attack ships with strafing would be tried in this battle . The Allied Air Forces also adopted other innovative tactics . In February 1942 , the RAAF began experimenting with skip bombing , an anti - shipping technique used by the British and Germans . Flying only a few dozen feet above the sea toward their targets , bombers would release their bombs , which would then , ideally , ricochet across the surface of the water and explode at the side of the target ship , under it , or just over it . A similar technique was mast - height bombing , in which bombers would approach the target at low altitude , , at about , and then drop down to mast height , at about from the target . They would release their bombs at around , aiming directly at the side of the ship . The Battle of the Bismarck Sea would demonstrate that this was the more successful of the two tactics . The two techniques were not mutually exclusive : a bomber could drop two bombs , skipping the first and launching the second at mast height . Practice missions were carried out against the , a liner that had run aground in 1923 . The Fifth Air Force had two heavy bomber groups . The 43rd Bombardment Group was equipped with about 55 Boeing B - 17 Flying Fortress es . Most of these had seen hard war service over the previous six months and the availability rate was low . The recently arrived 90th Bombardment Group was equipped with Consolidated B - 24 Liberator s , but they too had maintenance problems . There were two medium groups : the 38th Bombardment Group , equipped with B - 25 Mitchells , and the 22nd Bombardment Group , equipped with Martin B - 26 Marauder s , but two of the former ’ s four squadrons had been diverted to the South Pacific Area , and the latter had taken so many losses that it had been withdrawn to Australia to be rebuilt . There was also a light group , the 3rd Attack Group , equipped with a mixture of Douglas A - 20 Havoc s and B - 25 Mitchells . This group was not just short of aircraft ; it was critically short of aircrew as well . To make up the numbers the USAAF turned to the RAAF for help . Australian aircrew were assigned to most of the group ’ s aircraft , serving in every role except aircraft commander . In addition to the RAAF aircrew with the USAAF squadrons , there were RAAF units in the Port Moresby area . No . 30 Squadron RAAF , which had arrived in Port Moresby in September 1942 , was equipped with the Bristol Beaufighter . Both the aircraft and the squadron proved adept at low level attacks . Also in the Port Moresby area were the 35th and 49th Fighter Group s , both equipped with Bell P - 400 , Curtiss P - 40 Warhawk and Lockheed P - 38 Lightning fighters , but only the latter were suitable for long range escort missions . Battle . First attacks . The Japanese convoy – comprising eight destroyer s and eight troop transport s with an escort of approximately 100 fighter s – assembled and departed from Simpson Harbour in Rabaul on 28 February . During the January operation , a course was followed that hugged the south coast of New Britain . This had made it easy to provide air cover , but being close to the airfields also made it possible for the Allied Air Forces to attack both the convoy and the airfields at the same time . This time , a route was chosen along the north coast , in the hope that the Allies would be deceived into thinking that the convoy ’ s objective was Madang . Allied air attacks on the convoy at this point would have to fly over New Britain , allowing easy interdiction from Japanese air bases there , but the final leg of the voyage would be particularly dangerous , because the convoy would have to negotiate the restricted waters of the Vitiaz Strait . The Japanese named the convoy " Operation 81 . " The destroyers carried 958 troops while the transports took 5 , 954 . All the ships were combat loaded to expedite unloading at Lae . The commander of the Japanese XVIII Army – Lieutenant General Hatazō Adachi – travelled on the destroyer , while that of the 51st Division – Lieutenant General Hidemitsu Nakano – was on board the destroyer . The escort commander – Rear Admiral Masatomi Kimura of the 3rd Destroyer Flotilla – flew his flag from the destroyer . The other five destroyers were , , , and . They escorted seven Army transports : " Aiyo Maru " ( 2 , 716 gross register tons ) , " Kembu Maru " ( 950 tons ) , ( 5 , 493 tons ) , " Oigawa Maru " ( 6 , 494 tons ) , ( 3 , 793 tons ) , ( 2 , 883 tons ) and " Teiyo Maru " ( 6 , 870 tons ) . Rounding out the force was the lone Navy transport " Nojima " ( 8 , 125 tons ) . All the ships carried troops , equipment and ammunition , except for the " Kembu Maru " , which carried 1 , 000 drums of avgas and 650 drums of other fuel . The convoy , moving at , was not detected for several days because of two tropical storms that struck the Solomon and Bismarck Seas between 27 February and 1 March , but at about 15 : 00 on 1 March , the crew of a patrolling B - 24 Liberator heavy bomber spotted the convoy . Eight B - 17 Flying Fortresses were sent to the location but failed to locate the ships . At dawn on 2 March , a force of six RAAF A - 20 Bostons attacked Lae to reduce its ability to provide support . At about 10 : 00 , another Liberator found the convoy . Eight B - 17s took off to attack the ships , followed an hour later by another 20 . They found the convoy and attacked with bombs from . They claimed to have sunk up to three merchant ships . " Kyokusei Maru " had sunk carrying 1 , 200 army troops , and two other transports , " Teiyo Maru " and " Nojima " , were damaged . Eight Japanese fighters were destroyed and 13 damaged in the day ’ s action . The destroyers " Yukikaze " and " Asagumo " plucked 950 survivors of " Kyokusei Maru " from the water . These two destroyers , being faster than the convoy since its speed was dictated by the slower transports , broke away from the group to disembark the survivors at Lae . The destroyers resumed their escort duties the next day . The convoy – without the troop transport and two destroyers – was attacked again on the evening of 2 March by 11 B - 17s , with minor damage to one transport . During the night , PBY Catalina flying boat s from No . 11 Squadron RAAF took over the task of shadowing the convoy . Further attacks . By 3 March , the convoy was within range of the air base at Milne Bay , and eight Bristol Beaufort torpedo bomber s from No . 100 Squadron RAAF took off from there . Because of bad weather only two found the convoy , and neither scored any hits , but the weather cleared after they rounded the Huon Peninsula . A force of 90 Allied aircraft took off from Port Moresby , and headed for Cape Ward Hunt , while 22 A - 20 Bostons of No . 22 Squadron RAAF attacked the Japanese fighter base at Lae , reducing the convoy ’ s air cover . Attacks on the base continued throughout the day . At 10 : 00 , 13 B - 17s reached the convoy and bombed from medium altitude of 7 , 000 feet , causing the ships to maneuver which dispersed the convoy formation and reduced their concentrated antiaircraft firepower . The B - 17s attracted a number of Mitsubishi A6M Zero fighters , which were in turn attacked by the P - 38 Lightning escorts . A B - 17 broke up in the air , and its crew was forced to take to their parachutes . Japanese fighter pilots machine - gunned some of the B - 17 crew members as they descended and attacked others in the water after they landed . Five of the Japanese fighters strafing the B - 17 aircrew were promptly engaged and shot down by three Lightnings , which were also lost . The Allied fighter pilots claimed 15 Zeros destroyed , while the B - 17 crews claimed five more . Actual Japanese fighter losses for the day were seven destroyed and three damaged . B - 25 arrived shortly afterward and released their 500 - pound bombs between 3 , 000 to 6 , 000 feet , reportedly causing two Japanese vessels to collide . The result of the B - 17 and B - 25 sorties scored few hits but left the convoy ships separated making them vulnerable to strafers and masthead bombers , and with the Japanese antiaircraft fire being focused on the medium - altitude bombers this left an opening for minimum altitude attacks . The 13 Beaufighters from No . 30 Squadron RAAF approached the convoy at low level to give the impression they were Beauforts making a torpedo attack . The ships turned to face them , the standard procedure to present a smaller target to torpedo bombers , allowing the Beaufighters to maximise the damage they inflicted on the ships ’ anti - aircraft guns , bridges and crews in strafing runs with their four nose cannon s and six wing - mounted machine guns . On board one of the Beaufighters was cameraman Damien Parer , who shot dramatic footage of the battle . Immediately afterward , seven B - 25s of the 38th Bombardment Group ’ s 71st Bombardment Squadron bombed from about , while six from the 405th Bombardment Squadron attacked at mast height . " Shirayuki " was the first ship to be hit , by a combination of strafing and bombing attacks . Almost all the men on the bridge became casualties , including Kimura , who was wounded . One bomb hit started a magazine explosion that caused the stern to break off , and the ship to sink . Her crew was transferred to " Shikinami " , and " Shirayuki " was scuttled . The destroyer " Tokitsukaze " was also hit and fatally damaged . Its crew was taken off by " Yukikaze " . The destroyer " Arashio " was hit , and collided with the transport " Nojima " , disabling her . Both the destroyer and the transport were abandoned , and " Nojima " was later sunk by an air attack . Fourteen B - 25s returned that afternoon , reportedly claiming 17 hits or near misses . By this time , a third of the transports were sunk or sinking . As the Beaufighters and B - 25s had expended their munitions , some USAAF A - 20 Havocs of the 3rd Attack Group joined in . Another five hits were claimed by B - 17s of the 43rd Bombardment Group from higher altitudes . During the afternoon , further attacks from USAAF B - 25s and Bostons of No . 22 Squadron RAAF followed . Garrett Middlebrook , a co - pilot in one of the B - 25s , described the ferocity of the strafing attacks : All seven of the transports were hit and most were burning or sinking about south east of Finschhafen , along with the destroyers " Shirayuki " , " Tokitsukaze " and " Arashio " . Four of the destroyers – " Shikinami " , " Yukikaze " , " Uranami " and " Asagumo " – picked up as many survivors as possible and then retired to Rabaul , accompanied by the destroyer , which had come from Rabaul to assist . That night , a force of ten U . S . Navy PT boat s – under the command of Lieutenant Commander Barry Atkins – set out to attack the convoy . Two boats struck submerged debris and were forced to return . The other eight arrived off Lae in the early hours of 4 March . Atkins spotted a fire that turned out to be the transport " Oigawa Maru " . " PT - 143 " and " PT - 150 " fired torpedoes at it , sinking the crippled vessel . In the morning , a fourth destroyer – " Asashio " – was sunk when a B - 17 hit her with a bomb while she was picking up survivors from " Arashio " . Some 2 , 700 survivors were taken to Rabaul by the destroyers . On 4 March , another 1 , 000 or so survivors were adrift on rafts . On the evenings of 3 – 5 March , PT boats and planes attacked Japanese rescue vessels , as well as the survivors from the sunken vessels on life rafts and swimming or floating in the sea . This was later justified on the grounds that rescued servicemen would have been rapidly landed at their military destination and promptly returned to active service , as well as being retaliation for the Japanese fighter planes attacking survivors of the downed B - 17 bomber . While many of the Allied aircrew accepted these attacks as being necessary , others were sickened . On 6 March , the Japanese submarines and picked up 170 survivors . Two days later , " I - 26 " found another 54 and put them ashore at Lae . Hundreds made their way to various islands . One band of 18 survivors landed on Kiriwina , where they were captured by " PT - 114 " . Another made its way to Guadalcanal , only to be killed by an American patrol . On 4 March the Japanese mounted a retaliatory raid on the Buna airfield , the site of a base that the Allies had captured back in January , though the fighters did little damage . Kenney wrote in his memoir that the Japanese reprisal occurred " after the horse had been stolen from the barn . It was a good thing that the Nip air commander was stupid . Those hundred airplanes would have made our job awfully hard if they had taken part in the big fight over the convoy on March 3rd . " On Goodenough Island , Australian patrols from the 47th Infantry Battalion found and killed 72 Japanese , captured 42 , and found another nine dead on a raft between 8 and 14 March 1943 . One patrol killed eight Japanese that had landed in two flat - bottomed boats , in which were found some documents in sealed tins . On translation by the Allied Translator and Interpreter Section one document turned out to be a copy of the Japanese Army List , with the names and postings of every officer in the Japanese Army . It therefore provided a complete order of battle of the Japanese Army , including many units that had never before been reported . A mention of any Japanese officer could now be correlated with his unit . Copies were made available to intelligence units in every theatre of war against Japan . Aftermath . The battle was a disaster for the Japanese . Out of 6 , 900 troops who were badly needed in New Guinea , only about 1 , 200 made it to Lae . Another 2 , 700 were saved by destroyers and submarines and returned to Rabaul . About 2 , 890 Japanese soldiers and sailors were killed . The Allies lost 13 aircrew , 10 of whom were lost in combat while three others died in an accident . There were also eight wounded . Aircraft losses were one B - 17 and three P - 38s in combat , and one B - 25 and one Beaufighter in accidents . MacArthur miscounted , and issued a communiqué on 7 March claiming that 22 ships , including 12 transports , three cruisers and seven destroyers , had been sunk along with 12 , 792 troops . Army Air Force Headquarters in Washington , D . C . looked into the matter in mid - 1943 and concluded that there were only 16 ships involved , but GHQ SWPA elected to stick to its original story . After the war , Kenney would repeat the claim . The Allied Air Forces had used 233 , 847 rounds of ammunition , and dropped 261 500 - pound and 253 thousand - pound bombs . They claimed 19 hits and 42 near misses with the former , and 59 hits and 39 near misses from the latter . Of the 137 bombs dropped in low level attacks , 48 , or 35 percent , were claimed to have hit , but only 29 , or 7 . 5 percent , of the 387 bombs dropped from medium altitude . This compared favourably with efforts in August and September 1942 when only 3 percent of bombs dropped were claimed to have scored hits . It was noted that the high and medium altitude attacks scored few hits but dispersed the convoy , while the strafing runs from the Beaufighters had knocked out many of the ships ' anti - aircraft defences . Aircraft attacking from multiple directions had confused and overwhelmed the Japanese defences , resulting in lower casualties and more accurate bombing . The results therefore vindicated not just the tactics of mast height attack , but of mounting coordinated attacks from multiple directions . The Japanese estimated that at least 29 bombs had hit a ship during the battle . This was a big improvement over the Battle of Wau back in January , when Allied aircraft attacked a Japanese convoy consisting of five destroyers and five troop transports travelling from Rabaul to Lae , but managed to sink just one transport and beach another . There was no doubt that the Japanese had suffered a major defeat . Imamura ' s chief of staff flew to Imperial General Headquarters to report on the disaster . It was decided that there would be no more attempts to land troops at Lae . The losses incurred in the Bismarck Sea caused grave concern for the security of Lae and Rabaul . This resulted in a change of strategy . On 25 March a joint Army - Navy Central Agreement on South West Area Operations gave operations in New Guinea priority over those in the Solomon Islands campaign . The XVIII Army was allocated additional shipping , ordnance and anti - aircraft units , which were sent to Wewak or Hansa Bay . Of the defeat , Rabaul staff officer Masatake Okumiya said , " Our losses for this single battle were fantastic . Not during the entire savage fighting at Guadalcanal did we suffer a single comparable blow . We knew we could no longer run cargo ships or even fast destroyer transports to any front on the north coast of New Guinea , east of Wewak . " The planned movement of the 20th Division to Madang was revised in the light of events in the Bismarck Sea . The operation was postponed for two days , and the destination was altered from Madang to Hansa Bay further west . To reduce the Allied air threat , the Allied airfield at Wau was bombed on 9 March , and that at Dobodura on 11 March . Three Allied aircraft were destroyed on the ground , and one P - 40 was lost in the air , but the Allied fighters claimed to have shot down nine Japanese planes . The transports reached Hansa Bay unscathed on 12 March , and the troops made their way down to Madang on foot or in barges . The 20th Division then became involved in an attempt to construct a road from Madang to Lae through the Ramu and Markham Valley s . It toiled on the road for the next few months , but its efforts were ultimately frustrated by New Guinea ' s weather and the rugged terrain of the Finisterre Range . Some submarines were made available for supply runs to Lae , but they did not have the capacity to support the troops there by themselves . An operation was carried out on 29 March in which four destroyers successfully delivered 800 troops to Finschhafen , but the growing threat from Allied aircraft led to the development of routes along the coast of New Guinea from Madang to Finschhafen , and along both the north and south coasts of New Britain to Finschhafen , and thence to Lae using Army landing craft . It was by this means that the remainder of the 51st Division finally made the trip to Lae in May . The necessity of delivering troops and supplies to the front in this manner caused immense difficulties for the Japanese in their attempts to halt further Allied advances . After the war , Japanese officers at Rabaul estimated that around 20 , 000 troops were lost in transit to New Guinea from Rabaul , a significant factor in Japan ' s ultimate defeat in the New Guinea campaign . In April , Admiral Isoroku Yamamoto used the additional air resources allocated to Rabaul in Operation " I - Go " , an air offensive designed to redress the situation by destroying Allied ships and aircraft in New Guinea and the Solomon Islands . The operation was indecisive , and Yamamoto himself became a casualty of Allied intelligence and air power in the Solomon Islands later that year . Game theory . In 1954 , O . G . Haywood , Jr . , wrote an article in the " " in which game theory was used to model the decision making in the battle . Since then , the name of the battle has been applied to this particular type of two - person zero - sum game .