- 82 - Pacific War - Operation Cartwheel starts rolling, June 6-20, 1943

Last time we spoke about the aftermath of the battle for Attu. The American victory over Attu meant the end of the Aleutian campaign for the Japanese, Tokyo decided to pull everyone out. Over 6000 Japanese needed evacuation from Kiska and it would be very tricky for the Japanese to get past Admiral Kinkaids blockade. Then we finished up the West Hubei offensive, with a part of it being known colloquially as the Rice Bowl Campaign. The Japanese had brutalized the Chinese, but we’re stopped short of invading Chongqing or Sichuan. Thus for the Chinese it was a victory, but at the same time the Japanese had secured exactly what they wanted, stealing vast amounts of property, notably rice. Vessels left Yichang and sailed further west through the riverways acquiring large sums of goods to help the China war cause. Today we are diving back into the south Pacific.

This episode is Operation Cartwheel starts rolling

Welcome to the Pacific War Podcast Week by Week, I am your dutiful host Craig Watson. But, before we start I want to also remind you this podcast is only made possible through the efforts of Kings and Generals over at Youtube. Perhaps you want to learn more about world war two? Kings and Generals have an assortment of episodes on world war two and much more  so go give them a look over on Youtube. So please subscribe to Kings and Generals over at Youtube and to continue helping us produce this content please check out www.patreon.com/kingsandgenerals. If you are still hungry for some more history related content, over on my channel, the Pacific War Channel you can find a few videos all the way from the Opium Wars of the 1800’s until the end of the Pacific War in 1945. 

So honestly for awhile now we have been hitting the North Pacific and China theaters, which certainly was a change of pace, but as you can imagine these events do not simply move along in a vacuum. Yes a lot was going on in the other theaters and this episode is going to be tackling a lot of different events so buckle up buckos. First we are going to talk about Operation Cartwheel.

The ULTRA intelligence that brought Yamamoto’s death was not the only information the Americans received in April. A lifeboat bearing a list of the names of 40,000 active Japanese officers washed ashore after the battle of the Bismarck Sea. Using this Cryptographers were able to match each name to radio signals from Japanese army units, ensuring General MacArthurs intelligence remained as operationally up to date as it could be. At the same time William Bull Hasley showed to on April 15th to Brisbane to meet with MacArthur and the two hit it off. Halsey would later write this about their first encounter. “Five minutes after I reported, I felt as if we were lifelong friends. I have seldom seen a man who makes a quicker, stronger, more favorable impression. He was then sixty-three, but he could have passed as fifty. His hair was jet black; his eyes were clear; his carriage erect….My mental picture poses him against the background of these discussions; he is pacing his office, almost wearing a groove between his large, bare desk and the portrait of George Washington that faced it; his corncob pipe is in his hand (I rarely saw him smoke it): and he is making his points in a diction I have never heard surpassed. “ Both men would hammer out a plan on April 26th, it was a revision to MacArthur’s Elkton plan, this one would be known as Elkton III, but it was soon to be coded as Operation Cartwheel. 

The plan consisted of 13 amphibious landings in just 6 months with MacArthur and Halsey providing maximum support to each others efforts. The first phase of the plan would see MacArthur seizing Woodlark and the Kirwina islands while Hasley invaded New Georgia. Phase 2 would commence 2 months after the start of the offensive where MacArthur would capture Lae, Salamaua and Finschhafen. Phase 3 would be the seizure of the Shortland islands and Bougainville in the south pacific. In December MacArthur would seize Cape Gloucester in Western New Britain and shortly after that they would seize Rabaul. Halsey’s forces would knock out Japanese air bases on Buka, allowing MacArthurs men to clear the northwestern half of New Guinea. By January of 1944, MacArthur and Halsey figured they would be ready for the final assault on Rabaul which was their ultimate objective for victory.

MacArthur resisted sending details of their joint plan to Washington, probably fearing the Europe first obsessed chiefs of staff would veto their ambitious thrust. He told them only that he anticipated that the first move toward Woodlark and Kirwina would start in June. However this was too slow for Admiral King. King wanted his protege Admiral Nimitz to begin a thrust into the central pacific, heading through the Marshalls in November and proposed shifting the Marine 1st and 2nd divisions, the ones that fell under MacArthurs and Halsey’s command to help with the Marshalls offensive, this alongside two bomber groups promised to General Kenney. MacArthur was very pissed off and he sent a distressed message to George Marshall damning the entire central Pacific strategy as a quote “unnecessary and even wasteful diversion from what should be the main pacific strategy”,  that being MacArthur’s own.”. He added in “from a broad strategic viewpoint, I am convinced that the best course of offensive action in the Pacific is a movement from Australia through New Guinea to Mindanao. Air supremacy is essential to success, for the southwestern strategy where large numbers of land-based aircraft are utterly essential and will immediately cut the enemy lines from japan to his conquered territory to the southward. Pulling any additional heavy bombers groups would in my opinion, collapse the offensive effort in the southwest pacific area…in my judgment the offensive against Rabaul should be considered the main effort, and it should not be nullified or weakened ”.

But King was adamant. There would indeed be a thrust through the central pacific led by the navy with its main axis passing through the Marshalls and Marianas towards Japan,which might I remind you listening, bypasses the Philippines. It of course was a strategy completely at odds with MacArthurs. Marshall supported King, as did the other Joint Chiefs. But in the end MacArthurs whining forced King to relent on the transfer of the two marine divisions and the bomber groups, thus MacArthur revealed his timetable for operation Cartwheel. He told them he planned to take Kiriwna and Woodlark in the Trobriand Island around June 30th. The advance on New Georgia would start on the same date, and in September the First Cavalry and 3 Australian divisions would begin operations against the Madang-Salamaua area. Meanwhile MacArthur's 43rd division would invade southern Bougainville on October 15th, while the 1st Marines and 32nd division would invade Cape Gloucester on December 1st. 

For all of these amphibious landings, there were no serious problems when it came to shipping and landing craft….that is for Nimitz designated areas. However at the beginning of 1943, MacArthur had practically no amphibious equipment nor experts in these types of operations. The only units available to him were the Army’s engineering special boat brigade which had very few small craft. The man who would be responsible for the amphibious assaults during much of the coming campaigns was to be Rear Admiral Daniel Barbey. On January 10th, 1943 he took command of the forces that would later be designated the 7th Amphibious force. Barbey from the offset established good relations with MacArthur…because well anyone who worked with MacArthur had to. He had nearly nothing to work with in the beginning, but started with establishing bases at Toobul Bay, near the mouth of the Brisbane river and Point Stephens. MacArthur had requested more small craft and transports as early as mid 1942, but because of the European and central pacific being a priority, little had come his way. Before the equipment came, MacArthur was receiving American and Australian troops, so he got Barbey’s team to improvise. They began training the troops in debarking from larger ships down cargo nets to smaller landing craft. However Barbey had no attack transports (APA), which was the key to this kind of operation. To solve this they rigged nets from cliffs, boy that must have been fun. The first Landing ship tanks LSTs and Landing craft tanks LCTs would not arrive until mid january, and on Easter Sunday 13 Landing craft infantry’s LCI’s were delivered, giving them very little time before the first operations were to begin to train the crews on how to use them. 

Now on the other side Halsey had his own three phase operation. Part 1 saw the invasion of New Georgia, part 2 was the seizure of Buin and Rekata Bay if possible and last 3 was the seizure of Kieta and the neutralization of Buka. Phase 1 was codenamed Operation Toenails. Halsey described the operation to Nimitz as “a infiltration and staging operation”. The operation would see simultaneous landings at Wickham Anchorage to hit its landing craft base; Segi point for its airfield site; Viru Harbor for its small craft base and Rendova Harbor which would serve as a new base to stage troops for a future attack upon Munda. This would all occur on June 30th. The main force assigned to Operation Toenails was General Hester’s 43rd division. Admiral Turner and his Task Force 31 were in charge of the amphibious landings while Admiral Fitch would toss 1182 aircraft to give them aircower and Admiral’s Ainsworth and Merrill’s Task force 36 would provide further naval support.

On the other side, interservice coordination between the Japanese Generals and Admirals remained intermittent and largely ad hoc, when it was not hostile. General Imamura’s 8th area army HQ at Rabaul stood above Hyakutake’s 17th Army, comprising 3 divisions spread over the SOlomons and New Britain, and General Hatazo Adachi’s 8th Army had 3 divisions on New Guinea. Troop reinforcements were arriving in Rabaul bolstering the garrison at one point to 90,000 men. Vice Admiral Jinichi Kusaka remained in command of navy forces at Rabaul and held responsibility for the defense of the central solomons. Admiral Mineichi Koga had succeeded the slain Yamamoto as commander in chief of the combined fleet, based at Truk. Nowhere in the theater was there a blended command, the army and navy had to coordinate their operations through a meticulous process of “nemawashi / digging around the roots” for a consensus. The Japanese moved new air units into the theater, including more of the elite carrier aircrews that had trained and honed their skills prior to the war, but the loss ratios in air combat was ruining them. 

As a result of the devastating loss during the battle of the Bismarck Sea, the Japanese were forced to change plans. USAAF and RAAF aircraft based at Port Moresby and Milne Bay had slaughtered an entire convoy of Japanese transports attempting to land troops in the Lae-Slaamaua area using a new technique called “skip bombing”. Imperial General HQ set up a joint Army/Navy investigation board to study the disaster, seeing the IJA accused the IJN of being too focused on the Solomons rather than on New Guinea. The Army argued New Guinea was vital for the national defenses and proposed that if a retreat became necessary, it would be as a direct result of the navy’s lack of support. If this were to happen they would have to pull back and create a defensive line from northwest New Guinea to Timor. The Navy’s representatives argued that the Huon Peninsula must be held or its loss would swing open the western gate to Rabaul, forcing the combined fleet to withdraw from Truk. Well the fighting eventually resulted in an ultimatum with both sides agreeing the army/navy operations should focus on eastern New Guinea.

It was decided that both the army and navy would literally operate as one unit, because that would go well. The Central solomons were still under the overall responsibility of the 8th fleet, now commanded by Vice Admiral Baron Samejima Tomoshige with some IJA units placed under naval command according to agreements made between General Imamura and Admiral Kusaka. It seems the Japanese could get along once and awhile, as just like Halsey and MacArthur, Imamura and Kusaka developed a deep friendship. Both of their staffs ate lunch together once or twice a week, where southeast area affairs were discussed informally and their respective staffs got to know another personally. Kusaka went on the record to say Imamura was a very great person. Many army units would be sent to reinforce the New Georgia defenses and by late May the bulk of the 229th regiment arrived to Munda, and the 13th regiment went to Vila by late June. Imamura placed both regiments under the command of Major General Sasaki Noboru’s southeast detachment who responded directly to Samejima. Samejima’s first orders were to arrange the responsibilities between General Sasaki’s southeast detachment and Admiral Ota’s 8th combined SNLF, seeing Sasaki in charge of Munda and Ota in charge of the Enogai and Bairoko area’s. If the situation arose, command would be unified under the senior officer on New Georgia, General Sasaki. Ota would also have responsibility for coastal artillery defense, radio communications, and barge operations.

Admiral Koga in his new role as commander of the combined fleet, preemptively sent move of his forces back to the home islands in preparation to reinforce Attu. But as the fate of the Aleutians became sealed by late May, Koga decided to concentrate the combined Fleet at Truk, so it would be primed and ready for a decisive naval battle with the Americans. Without the aid of Koga’s carriers, Kusaka had launched another air counteroffensive after I-Go, this one taking place in June. The aim was yet again to prevent the Americans from invading the central solomons . Kusaka began tossing waves of Bety’s against American shipping east of San Cristobal and night raids over guadalcanal. Simultaneously he also unleashed Operation SO; a major offensive to smash allied air power in the Solomon islands; and operation SE: which targeted airfields and shipping. He sent 105 Zeros to sweep and bomb the enemy airfields with a new type of gasoline bomb. Operation SE began with 25 Val dive bombers attacking US shipping in the Guadalcanal-Tulagi area and Operation SO began on June 7th with 81 Zeros led by Lt Commander Shindo Saburo assaulting the Russels. However the Russel group ran right into 104 allied fighters who shot down 9 Zeros. A follow up attack was made on the 12th with 74 Zeros led by Lt Miyano Zenjiro, this time the Japanese lost 7 fighters but took down 6 American. As usual the Japanese pilots made wild claims, stating the first attack saw 41 American fights shot down and the second attack 24. 

Kusaka launched the main attack of Operation SE on June 16th led by Lt commander Saburo consisting of 24 Vals and 70 Zero escorts who swung south of the Russells, turning at Beaufort Bay. Yet again they were intercepted, this time by 74 allied fighters over BEaufort Bay and the ensuing ari battle rolled over the mountainous spine of guadalcanal. This time the Japanese lost 15 Zeros and 13 Vals while only shooting down 6 allied fighters. The Japanese lost first rate pilots such as Lt Miyano who had scored a total of 16 kills during the war. Again Japanese veteran pilots were being bled dry severely affecting the nation's airpower. Despite their waves being intercepted nearly every time, the Vals were able to press through with their attacks and managed to hit the cargo ships Caleno and LST-340. But such results were hardly worth the cost, so Kusaka began to urgently request reinforcements. The carrier Ryhuo would lend her bombers to replace the lost ones, arriving on the 2nd of July. The losses taught the Japanese pilots some bitter lessons and never again would the fly over guadalcanal during daylight as the American CAP was far to powerful.

Over in New Guinea, General Blamey was laying out his plan for the capture of Lae, codenamed Operation Postern which was approved by MacArthurs headquarters. Before the allies would invade Woodlark and Kiriwana, MacArthur proscribed the seizure of Lae and the Markham and Ramu valley. The Markham operations were to be based on Port Moresby while the north coast operations would be staged from Buna and Milne Bay. The invasion of Woodlark and Kiriwana islands codenamed Operation Chronicle would be entrusted to Lt General Walter Kruegers 6th army. The islands northeast of the Papuan coast would allow the allies to have air bases closer to Japanese targets in the Solomons and around Rabaul, thus Blamey had devised his plan to secure the northeastern part of New Guinea. The first phase of his plan was Lae and the Markham and Ramu Valleys; the 2nd phase was to seize a shore base within 60 miles of Lae, he chose Nassau Bay. Nassau Bay would help with the supply problems in the Wau-Mubo-Bobdubi area, as all the supplies were being flown in from Port Moresby. The mountains were serious obstacles for transport aircraft, not to mention the Japanese fighters that could spring out of nearby Lae. Taking Nassau Bay would greatly shorting supply lines for allied troops fighting in the Salamaua region and also allow a junction to be made with General Saviges forces operating at Mubo

The 162nd American Regiment led by Colonel Archibald MacKechnie would help hit Nassau Bay, they would be known as the MacKechnie force. They would seize the high ground around Goodiew Junction and Mount Tambu and the ridges running down therefrom to the sea, allowing the Australians to link up with the 15th brigade at Bobdubi and the American landing force at Nassau. D-day for the Nassau Landing was set for June 30th and it was all going to act as a feint, hoping to lure Japanese forces from Lae to Salamaua. 

Now the last time we left off in New Guinea, General Savige had launched a limited offensive against the Japanese at Mubo and Bobdubi ridge. General Nakano was certain Salamaua was the main allied target and this prompting him on the 29th to order Major General Chuichi Muroya to lead the 51st division to fortify it. In the process Muroya’s men expelled Warfe’s commandos from the northern ridge. To the east of Mubo, Brigadier Moten was trying to take the Pimple, but his 17th brigade would be performing more patrolling than actual attacks throughout the later half of May. Eventually Savige would relieve the exhausted 2/7th battalion with the 2/6th battalion led by Lt Colonel Frederick Wood who would begin an advance on May the 27th. Meanwhile Nakano had brought more reinforcements to defend Mubo and launched a strong counterattack in early May, nearly breaking through towards the main Australian camp at Lababia ridge. On May 23rd Nakano received two battalions of the 66th regiment and began to work out a plan for assembling supplies and ammunition in the Mubo area to prepare for an offensive. Men would move at night in a single file along the narrow jungle trails carrying the materials by hand, through mud and rain. The main train was a slope on Komiatum ridge known to the Japanese as Regret Hill as the hard working soldiers became more exhausted with each passing day marching along it. The Japanese sought to clear out Lababia ridge as far as Guadagasal, thus securing Mubo.

On June 3rd, allied patrols discovered Nakano had reoccupied Markham point which forced Savige to keep the bulk of the 24th away from the action at Bobdubi and Mubo. From their camp at the bank of the Markham Savige ordered patrols to investigate the Nadzab area. On June 14th, a 3 man patrol came across friendly natives at the village of Gabsonkek who informed them of the Japanese activity in the area. They said "that the Japs come to the village every day between 10:00 and 12:00 hours taking everything in sight—pigs, fowls, fruit, etc., without paying; they take native girls back to Lae if they can catch them. The guides would not proceed farther to Ngasawapum because Japan man come up Big Road, cut us off", and they would not go to Narakapor because they claimed there were too many Japs and two big guns". The patrol went back to camp by the 18th informing command. A second patrol was made, led by Lt Dave Burke who forded the Tabali River to get to Nassau Bay. Their report indicated the area was suitable for landing and road construction. To further prepare for the American landings, the Australians began building a footbridge over the Bitoi River and blazed a track up to Bitoi Ridge. On Lababia Ridge the main defensive position withdrew to a junction on the Jap Tracks where it would be easier to counter enemy encirclement attempts.

Reports came in from forward platoons that there was considerable enemy activity along the Komiatum-Mubo track. This was Nakano’s 66th regiment carrying the food and ammunition in preparation for the upcoming offensive. In response to this, Savige ordered Brigadier Frank Hosking of the 15th brigade to assume command of the Bobdubi ridge area and to begin harassing the Japanese supply route. Meanwhile the 58th/59th battalion relieved the 2/3rd independent company at Hote and a party of Warfe’s commando’s were sent to attack the Komiatum-Mubo track. However disaster struck as the Australians ran into their own booby-traps on June 16th suffering a number of casualties. By June 20th, the commando’s established ambush positions along a ridge near the junction of Stephens Track and the Komiatum Track. They successfully ambushed some Japanese later that day, killing a few men and capturing valuable documents about the arrival of Nakano’s 66th regiment. However by this point Nakano’s units were already assembling in front of Lababia ridge and the offensive was about to begin. Now we gotta finish up the episode talking about some developments in India.

After the disastrous first Arakan Campaign, Marshal Wavell was to receive a promotion, and by promotion I mean he was kicked upstairs as they say, succeeded Lord Linlithgow as the new Viceroy of India. But until then he began looking into training his forces in jungle warfare as the bitter lessons learned at Arakan proved the men were very unprepared. Wavell also wanted to investigate what the hell had happened during the disaster, so he sent Major General Roland Richardson in late May to head a infantry committee at New Delhi for the task. The committee’s report about the Arakan campaign found the troops fighting spirit was fundamentally sound, but the major problems that affected their combat performance were more about the over expansion of the army in India. The army mobilization had been rushed, they barely met basic training and the supplying of their sheer numbers was a catastrophe. There were also issues regarding their low status, inferior pay for the infantry, which further deprived them of skilled and well educated recruits.  Yet above all else the Infantry committee found their lack of jungle training to be the most egregious issue. As observed “This is the most urgent problem facing us, and one which requires prompt and energetic action if results are to be produced in time for the winter campaigning season.” The lack of jungle training severely undermined their ability to fight efficiently and ultimately led to the breakdown of infantry battalions in the Arakan. And of course there was the ever present unseen enemy, that of malaria, alongside an assortment of other ailments that were wreaking havoc on the men.

But many of these problems could not be tackled until June 20th, when General Claude Auchinleck was officially appointed as the new Commander in Chief in India. For General Slim this was excellent news and certainly worked in his favor alongside the sacking of Irwin. The “Auk” as he was called, had always been a Slim supporter and was the one who recommended him to Wavell for advancement when Wavell was Commander in Chief of the middle east back in 1941. The Auk had wanted to retain Slim in the middle east and fought hard to dissuade Wavell from taking him over to Burma. Churchill never held Wavell ever in high regard and was tired of his quasi-academic effusions and preferred a “fighting general” in Burma. Alongside the Auk, Irwin was replaced with General George Giffard, and Slim had this to say of the replacement. 

“The new Army Commander had a great effect on me. A tall, goodlooking man in the late fifties, who had obviously kept himself physically and mentally in first-class condition, there was nothing dramatic about him in either appearance or speech. He abhorred the theatrical, and was one of the very few generals, indeed men in any position, I have known who really disliked publicity . . . But there was much more to General Giffard than good taste, good manners and unselfishness. He understood the fundamentals of war – that soldiers must be trained before they can fight, fed before they can march, and relieved before they are worn out. He understood that front-line commanders should be spared responsibilities in the rear, and that soundness of organization and administration is worth more than specious short-cuts to victory”

Auckinleck went to work from the offset of his new command by improving the welfare, health and feeding of the Indian army to foster improved morale. General Giffard as the new commander of the Eastern Army had Major General Temple Gurdon to oversee some reforms for training and the development of new doctrines. A lot of effort was made to conduct intensive collective training under jungle conditions. The men would train near Nasik, Ranchi, Dehradun and in the Jhansi-Nowgong-lalitpur region. Commanders low to high were given a chance at handling units to improve standards of staff work, practice combined army tactics and build team spirit. Auchinleck also initiated a policy of active patrolling at Assam and Arakan to gather intelligence and maintain touch with the Japanese as to destroy the feeling that they were super soldiers. 

 

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A lot of chess pieces were moved around the board this week. Bitter lessons had been learnt in multiple theaters of the war and now it came time to reorganize and try new things to ultimately bring the war against Japan to a closer end.