Operation: CAUSEWAY

Operation: CAUSEWAY

The Invasion that never was...


"The (US) Joint Chiefs of Staff have decided that our first major objective in the war against Japan will be the vital Luzon-Formosa-China Coast area...with an occupation of Formosa by target date 15 Oct. 1945.

It may be expected that the enemy will oppose the operation with full strength...and this opposition may be of an all out character."

Operation Causeway Preliminary Report June 21, 1944.

PHELIM KINE looks back at the decisions that saved Taiwan from what would have been one of the biggest invasions of modern military history.

The China News © Sunday, August 10, 1997, wishes to gratefully acknowledge the generous assistance of Mr. Robert B. Sheeks, Major, USMCR Retired, as the primary source of information for this article.

Half a million American troops. More than 4000 ships. Thousands of aircraft. In the summer of 1944, American military stratagists had begun preparartions for Operation Causeway, the codename for a massive invasion of Taiwan by air, sea and land.

Chronicle of an invasion survivor

Piles of books and historical texts about the Pacific war, sheaves of declassified US government documents. Copies of military maps detailing the Taiwan invasion landing zone as well as submarine and supply ship routes. For former US Marine intellegence officer, Robert B. Sheeks, the decades of interest and accumulation of data about Operation Causeway is rooted in very personal reasons. "I discovered after the war that my division (US Marine Corps 2nd Division) had been scheduled to be in the initial landing force on Taiwan," he explains. Cancellation of Operation Causeway, Sheeks admits, "greatly increased my chances of surviving to the end of the war."

Sheeks is no stranger to the grim calculus of invasion casualties. After several months of Japanese language training in the US in 1942, then Marine Lieutenant Robert B. Sheeks was assigned to assist in the interrogation of Japanese prisoners taken during the bloody island-hopping campaigns of Guadalcanal, Tarawa, Saipan and Tinian Islands. "The Tarawa Japanese military garrison consisted of 5000 troops. In the end I only escorted 19 (Japanese) survivors back to Pearl Harbor," Sheeks says sadly.

On Saipan, Sheeks was awarded the Bronze Star for "heroic achievement" due to his efforts in convincing hundreds of Japanese to surrender rather than fight to the death or commit suicide. "When large numbers of civilians were driven into hiding by our advance during the latter stages of operations, he moved with frontline units despite considerable personal danger, and utilized public address systems to call civilians and soldiers out of hiding, thereby effecting the surrender of large numbers of the enemy." Sheeks' Bronze Star citation reads.

In spite of the brutality of the Pacific campaign, for Sheeks and his fellow officers, the prospect of an invasion of Taiwan filled them with anticipation. "The prospect of invading Taiwan was important to us because it was so close to Japan," he explains. "It would have meant that the end of the war would have been in sight."

For Sheeks, the son of an American business family in Shanghai, a Taiwan invasion was also a symbolic step closer to "home" in China.

While the cancellation of Operation Causeway forstalled Sheeks' dream of returning to China through Taiwan, he did finally arrive in Taiwan as a US Consulate officer in 1949, as a result of another twist of history. "In 1948... I was assigned to the US Consulate General in Shanghai," he writes in a brief autobiography. "I was reassigned to the Consulate in Taipei, which later became the American Embassy."

Sheeks' tenure at the US Consulate and Embassy in Taipei as Public Affairs Officer and Director of the United States Information Service (USIS) from 1949-1951, began a five-decade relationship with Taiwan that continues to this day. Now working as a management consultant, Sheeks continues to do research on the aborted invasion of Taiwan for a series of articles he plans to write on that part of WWII. "It's one of the most facinating 'what-ifs' of the Second World War." Sheeks says, explaining his interest in the plan that he himself would have taken part in, "but it's something that most people have never heard of."

Targeting Fortress Formosa

It almost happened. Fifty-three years ago, military planners in Washington and the Pacific Command were putting the final touches to a plan to accelerate the defeat of Japan through the invasion of the Japanese home islands. The target: Taiwan.

In 1944, Taiwan, or Formosa as it was still known in the West, was entering it's 49th year within the Japanese empire, a part of the euphemistically-titled East Asia Co-Prosperity Sphere. From the earliest days of the Pacific war, Taiwan had proven its worth to its colonial masters, making considerable contributions to the Japanese war effort. From Taiwanese ports and airfields a reliable stream of men and material for Japanese operations had poured into the Philippines, the Malayan Peninsula and Indonesia.

"Taiwan was a transfer base for troops going between Japan and Southeast Asia, it was a good place to stockpile supplies," explains amateur military historian and former US consular officer in Taiwan, Robert B. Sheeks. "Taiwan also produced a lot of rice and other food the Japanese needed. "For the Japanese, Taiwan was like Japan's food bowl," Sheeks says.

Manpower was also a significant contribution Taiwan made to the Japanese war effort. Taiwanese conscripts were assigned to fight in the Pacific theater. Taiwanese aboriginal recruits in the Japanese Imperial Army proved particularly valuable in the Japanese offensive against American forces in the Philippines in 1941 and 1942. "Some of the aborigines from Taiwan were specially recruited to take part in the assault on Corregidor and Bataan," Sheeks says.

In spite of its role within the Japanese military machine, until mid 1944, the Pacific war remained, for most Taiwanese, a matter of newsreel footage and reports from Japanese troops in transit between combat areas. However, by the second half of 1944, events on the other side of the world had conspired to transform Taiwan from its position of safe obscurity to a point of essential strategic importance for the Allied Command.

For officers in Washington and throughout the Pacific, Taiwan was increasingly perceived as a key jumping-off point for the long-anticipated invasion of the Japanese home islands. "The Anglo-American invasion of France had succeeded and Army General MacArthur and Naval Admiral Nimitz were battering the inner ring of Japan's defenses from the Marianas and Western New Guinea." writes Phil Spector in his history of the Pacific war, "Eagle Against the Sun." "The question was where to go next."

Admiral Ernest King, US Chief of Naval Operations, was determined that Taiwan would be next. According to historian David Sommerville in his book "World War II, Day By Day," King perceived the capture of Taiwan as essential for "strangling" the Japanese home islands. "Admiral King believed that all sea and air lines of communication from Japan south could be effectively throttled by holding the Marianas, Formosa and a foothold on the China coast," Sommerville writes.

While the American Joint Chiefs of Staff had anticipated the necessity of an invasion of Taiwan in its "Strategic Plan for the Defeat of Japan" in the spring of 1943, Allied military successes in Europe had made the invasion of Taiwan appear far more realistic and achievable. The result was "Operation Causeway," a detailed outline of the assumptions, objectives and logistics of a massive land air, sea and land invasion of "Formosa and Amoy."

Issued on June 21, 1944, the now-declassified preliminary draft of Operation Causeway, stamped "Top Secret" and "Officer to Officer Handling Only", provides a fascinating and detailed glimpse of how the US planned to assualt Taiwan. The draft envisioned a successful invasion of Taiwan as an essential component in the defeat of Japan.

The elimination of Taiwan as supply depot and transfer point for Japanese troops, the island's easy access to Nationalist-held airfields on the eastern coast of China, as well as Taiwan's position as a convenient jumping-off point for attacks by American bombers on the Japanese home islands, made control of Taiwan seem extremely attractive to military planners. "(The invasion's) successful completion will permit the establishment of our forces in positions from which all parts of Japan may be bombed," the Operation Causeway preliminary draft predicted.

To invade and occupy Taiwan, the American Joint Chiefs of Staff' planned the largest invading force yet seen in the war. An attacking force of 302,000 US Army troops and 100,000 marines supported by thousands more in planes and ships, matched even the huge force which had taken part in the June 6 D-Day landings in France. However, later estimates regarding the scale of the invasion indicate that the numbers of troops required would have been even higher.

"I think the official estimates of what the invasion would have required were optimistic," Sheeks says today. "Considering the size of Taiwan and the traditional military ratio of having an invasion force at least three times larger than the defending forces, the true number of US forces necessary for the invasion would have been closer to 500,000, including land, sea, air and logistical support," he says.

Landing at four beachheads on Taiwan's southern coast between Kaoshiung and Kenting, the attacking forces would have consolidated control of the southern third of the island and then proceeded northward along the west coast toward the Japanese colonial administrative center at Taipei. "Development of airfields and port facilities devoted to bombing Japan would have been operational within the first couple of weeks of the invasion." Sheeks says. "Within 2-3 months, the island would effectively have been under Allied control for all practical purposes."

In spite of the intricately painstaking detail of Operation Causeway's preliminary draft, Taiwan was spared the onslaught of American military might by problems caused by the sheer scale of the invasion. Estimates of the troop numbers necessary for the invasion exceeded the number available in the entire Pacific area at the time, requiring the invasion to be postponed until a massive transfer of troops from the European theater of the war could be transferred to the Pacific. In light of this fact, General MacArthur's promise of a faster, easier route to the Japanese home islands by bypassing Taiwan and pursuing an invasion of the island of Luzon, proved persuasive to military planners at the time.

At the same time, one of the main strategic attractions and assumptions of the proposed invasion - the access to Allied-controlled air bases on the East China coast - vanished, as the result of a preemptive strike by Japanese forces. "The Japanese had correctly guessed that the US would try to support an invasion of Japan from China," Sheeks explains," so they quickly launched their own attacks to forestall this possibility, and occupied all airfields and ports along the East China coast."

In the end, General Douglas MacArthur's promise to "return" to the Philippines he abandoned in 1942 proved to be the decisive factor in shelving Operation Causeway. The proposal to take Taiwan was a threat to MacArthur's ambition to fulfill his dramatic vow, and he fought Operation Causeway tooth and claw in favor of "island-hopping" up the Philippines archipelago. "MacArthur had tunnel vision," Robert Sheeks says of the famous general's desire to reconquer the Philippines. "He wanted to return to the Philippines to the exclusion of other alternatives."

Map shown above provided, Courtesy of Robert B. Sheeks. A copy of the original battle plan for the military assault codenamed Operation Causeway, which would have sent hundreds of thousands of US Army, Navy and Air Force personnel pouring into Taiwan in an attempt to overwhelm the occupying Japanese forces. This top secret 1944 document has recently been declassified by the US Government.

MacArthur's popularity with the American public has led some military historians to conclude that President Roosevelt secretly traded his support for a Philippines invasion in return for the general's support in the upcoming presidential election in 1945. "MacArthur had not only force of personality, he had appeal to the American public who agreed with him when he said 'We should go back (to the Philippines)," Sheeks says. "MacArthur had the ability to attract or deflect votes for Roosevelt and some analysts conclude that a deal was struck between them."

On October 3, 1944, the decision of the Joint Chiefs of Staff to bypass Taiwan in favor of MacArthur's Philippine island strategy spelled the end of Operation Causeway. Taiwan was left, in MacArthur's words, "to wither on the vine." Although Taiwan was still subject to continual air attacks from 1943 to 1945, the abandonment of Operation Causeway spared the island massive devastation and the lives of thousands of Taiwanese civilians as well as those of Japanese and American troops. "A terrible tragedy was averted," Sheeks points out.


Invading Taiwan: inside Operation Causeway

TAIWAN'S SOUTHERN COAST IS NOW synonymous with the last vestiges of Taiwan's tropical seaside beauty. A half century ago, however, American military planners had very different plans for the beaches of Pingtung County. On detailed maps of the island, American strategists plotted naval artillery barrages, strafing runs, napalm attacks and troop landings in the heart of what is now the outdoor recreation center of Taiwan. A look through the former "top secret" plans for Operation Causeway reveals America's step-by-step plan to wrest Taiwan from control of the Japanese.

1. Blinding the Enemy: "Prior to the operations, the sea communications of Formosa and the Pescadores (Penghu) will be destroyed to the maximum extent practicable by the operations of submarines and by surface and air attacks on shipping." (Operation Causeway preliminary draft).

2. Invasion Day -3: Three days before the actual landing of troops, ships stationed off the south coast of Taiwan would "initiate intensive attacks by (aircraft carrier-based planes) in preparation for the assault."

3. Invasion Day -2: Air attacks would have been coordinated with bombardments of naval gunfire by the hundreds of gunships around the coast.

4. Invasion Day: On the day of the invasion itself, American army troops and marines would have hit the beaches at four different points. From each beachhead, the American troops were assigned specific targets such as airfields and river crossings. Their overall objective was the same, however. "... capture, occupy and defend and develop the western coastal plain of Formosa south of an east-west line through Tainan."

Kenting Beachhead: Troops that disembarked at Kenting would travel east to capture the coastal town of Kung Kuan before heading south to help create a protective perimeter line from Kenting to Tainan.

Linn Pien Beachhead: Troops from this landing were assigned to move north before splitting into two groups. One group would have continued north to capture the rail terminal at Kuan Hsing, while the other group would have veered west to assist in the operations around Kaoshiung (then known by its Japanese name of "Takao").

Tung Kang Beachhead: After disembarking, American troops would have rushed north to capture Pingtung City and its railhead.

Talinpu Beachhead: The task force that landed at Talinpu was assigned to capture the City of Fengshan and then proceed on to take the port city of Kaohsiung.

After consolidating control of the southern third of the island, Navy "Seabee" engineering units would have begun work on making the airfields suitable for fighter and bomber sorties on Northern Taiwan and the home islands of Japan.

Meanwhile, ground troops were assigned the grim task of pursuing the Japanese northward in extensive "mop up" operations.

"Thereafter, the expeditionary troops will advance northward and secure additional areas on the western coastal plain of Formosa to the maximum extent permitted by the means available." the draft states.

5. In a seamless sequence unknown outside of a small circle of military planners, the American strategists foresaw the landing of troops on Matsu and a further invasion of nearby coastal regions of China, twenty and forty days respectively after the initial Taiwan D-Day.

Amidst the dry, technical phraseology of the American invasion plans for Taiwan, the unusually blunt warning about the expected Japanese resistance to the attack stands out. But by mid-1944, American military planners were under no illusion about the ferocity of Japanese opposition to American landings. The thousands of American lives lost on the blood-soaked beaches of Tarawa, Saipan, Tinian and Guadalcanal had vanquished the hopes of even the most optimistic military planners that the Japanese would loosen their grip on their remaining Pacific holdings without a fight.

Throughout the American campaign to retake the Pacific islands lost to the Japanese forces at the outset of the war, the invaders had learned hard, costly lessons on how the Japanese could turn the most barren atolls into deathtraps that they were willing to defend to the last man. The intensity of the Japanese defense of Taiwan would, military experts agree, have matched the savage fighting of earlier Pacific campaigns.

Unlike previous invasion sites, Taiwan had remained relatively unscathed by military operations throughout much of the war. "On Taiwan (Japanese) morale was still high in 1944," Sheeks notes. "Taiwan was a nice place and it felt a lot like home (to the Japanese)."

The proximity of Taiwan to the home islands of Japan gave the defenders of the island an added sense of urgency. "Even though Taiwan was just a colony, it had been part of the Empire for a long time and was close enough to the home islands to make the Japanese want to fight to keep it." Sheeks adds.

Unlike previous military engagements in the Pacific war, the duration of the Japanese occupation on Taiwan had allowed the colonizers to develop valuable links with the local Taiwanese population. "Taiwan would have been an entirely different battle," Sheeks says, "Unlike the Philippines and other places, the local (Taiwanese) population had been "Japanized" to some extent."

"Japanization," Sheeks explains, meant that the Japanese defenders on Taiwan could count on the assistance of local Taiwanese troops and labor battallions to assist them in the event of an Allied invasion.

Indeed, the size of the Japanese forces lying in wait on Taiwan for invading American forces would have been exponentially higher than the relatively smaller groups of defenders encountered in previous battles. "There are now approximately 50,000 ground troops based on Formosa," a top secret US Army logistics memorandum on Operation Causeway reported on Aug. 17, 1944. "It is believed that (the Japanese) will probably have twice that number there by Jan.1945 in addition to 70,000 air force and service personnel."

The huge numbers of US troops needed to overwhelm this number of Japanese defenders of Taiwan would have been subject to torturous and possibly unreliable lines of supply that would have complicated their task immensely.

"There are no bases or depots to support the operation from an Army point of view, west of the West Coast of the US," the invasion plan's preliminary draft states soberly.

In contrast; the Japanese defenders would have been able to count on reinforcements and resupply from the relatively near home islands of Japan. "If (US forces) had been confined to the (landing points in the) south, (the Japanese} would have been bringing (reinforcements) into Keelung and other places up north." Sheeks states.

While the decision of the US Joint Chiefs of Staff on Oct. 3 to abandon Operation Causeway makes any discussion on the possible course and conduct of the US invasion of Taiwan highly speculative, Robert' Sheeks believes that history has provided a credible model for what such an invasion would have entailed. "(The battle of) Okinawa is a pretty good indictor of what would have happened on Taiwan. (Although) Okinawa is much more concentrated (in size) and closer to Japan than Taiwan; the Taiwan invasion could have been very similar," he says.

As they did on Okinawa, Sheeks says that defending Japanese forces on Taiwan, would probably have followed a "defense in depth" strategy. Invading forces would have been allowed to land, relatively unopposed, then would have been attacked in earnest as they gathered on the ground. "This type of strategy offered the Japanese three advantages," Sheeks explains. "They could conserve ammunition, have concentrated, easier targets, and expose more US supply ships anchored offshore to Kamikaze attacks."

Like Okinawa, Taiwan offered unique geographical formations that would have maximized the defense capabilities of the Japanese forces dug in against the invading Americans. "On Okinawa the Japanese used traditional Chinese style graves dug into hillsides as ready-made machine gun and mortar bases," Sheeks says, "and no doubt they would have used similar tactics here in Taiwan."

Advancing northward up Taiwan's western coast, the western foothills would have offered the defenders an age-old natural advantage. "The western coast area doesn't offer much in the way of natural cover," Sheeks notes, "It's basically agricultural plain with some shallow rivers running across it." "The Japanese would have attacked the Americans from the hills in the same way that aborigines had attacked Japanese forces when they first arrived in Taiwan."

Progress up the island to the northern tip would be characterized by "meter-by-meter-fighting," Sheeks says, culminating in a "prolonged battle" with retreating Japanese forces in the mountains near Keelung. "I don’t think (the invading force) would have been driven off of Taiwan by the Japanese" Sheeks concludes, "but there would have been some costly warfare, particularly around the mid-western coast of the island."

The victory of Allied forces over the Japanese in Taiwan that Sheeks assumes in retrospect would have been costly indeed. Estimates by wartime planners of the predicted casualties involved in the taking of Taiwan were, some analysts contend, the final decisive factor in favor of MacArthur's long-sought Philippine island invasion instead. Based on estimates extrapolated from the casualty figures of the Saipan invasion, the US military predicted at least 150,000 American dead and wounded resulting from an invasion of Taiwan.

More tragic still would have been the even higher civilian casualties resulting from the intense, extended bombardment the island would come under from both the sea and land. "(The Americans) would have pounded (Taiwan) and just kept pounding it," Robert Sheeks observes. "The civilian population of Taiwan would have suffered tremendously, as it did in Okinawa."

Most interesting in the contemplation of the 'what-ifs' of the results of a successful American invasion of Taiwan is the effect an extended American occupation of the island would have had on the relationship of mainland China and Taiwan. "Taiwan would inevitably been under a post-war American occupation, similar to that of Okinawa and the rest of Japan, for at least two years," Sheeks observes.

The effects of such a large American presence so close to the Chinese mainland during the throes of the Chinese civil war could very well have changed world history. "The US perhaps would not have allowed the Nationalists to come to Taiwan from the mainland immediately," Sheeks says, "but the chances are the US would have been inclined to give more (military) backing to the Nationalists on the mainland against the Japanese, because of the large American presence on Taiwan."

For the people of Taiwan, the bloody and brutal invasion of their island might have fundamentally changed the destiny of their homeland. "Eventually," Sheeks says, "the US occupation forces would probably have had to turn Taiwan back to the Nationalists or allowed the island to determine its own future."

Reflecting on his own experiences in other liberated areas of the Pacific, Sheeks raises one other intriguing possibility of what may have become of Taiwan in the wake of a successful American invasion of the island. "People (in Taiwan) might have done what people said to me in Saipan and Okinawa after the invasions there," Sheeks says with a smile. "People would come up to me and say 'Can we come under American protection?' 'Can we become part of the US?"

Questions and Comments: Send email to BobSheeks@aol.com