The United States interrupted its invasion of Taiwan during World War II; The move has lessons for China today

• The United States considered invading Japanese-occupied Taiwan during World War II.
• Top American commanders decided it would be a nightmare with a high number of casualties.
• Chinese invaders may face similar challenges today.

The United States once planned to invade and occupy Taiwan on a scale as large as D-day.

Operation Causeway involved sending hundreds of thousands of troops, supported by thousands of ships and aircraft, to storm the beaches of Japanese-occupied territory in 1945.

“An invasion would almost certainly be a terrible spectacle and a nightmarish ordeal,” said Ian Easton, an analyst who authored the new report test regarding the invasion of the Chinese Institute of Maritime Studies. “Much worse than any battle that actually took place in the Pacific. The campaign would be protracted and could take six months or even a year.”

The CMSI study clearly shows that a United States invasion of Taiwan in 1945 – or a Chinese invasion today – would be difficult and risky.

Like many years ago, today’s Taiwan would likely have the Japanese fortifications and tactics to defeat a major Chinese amphibious attack – illustrating the risks and dangers of any attempt to seize the island that Beijing views as a separatist province.

“Long and Protracted Fight”

The genesis of the planned American invasion – eventually called Operation Causeway – began in the late 1920s, when the United States Navy and Army developed a strategy for a potential war with Japan. The Orange War Plan envisaged an attack across the Pacific, culminating in an attack on Taiwan – then called Formosa – which the Japanese Empire annexed from China in 1895, after the First Sino-Japanese War. The plan was to occupy Taiwan with 90,000 Army and Marine troops, which would turn the island into a staging ground for an invasion of Japan. In the 1930s, Taiwan was rejected in favor of taking Okinawa, a smaller target closer to Japan’s four largest islands.

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In 1944, with Japan disintegrating and an invasion of the Japanese mainland seeming likely, American planners again considered Taiwan as a landing point and a base for B-29 Superfortress strategic bombers. Navy Adm. Ernest King favored the Taiwan option, while Gen. Douglas MacArthur lobbied for an invasion of the Philippines. For a time, “General MacArthur’s return to the Philippines was viewed as a secondary and supporting campaign,” according to the CMSI study.

Initial plans called for an assault by 12 divisions in early 1945. However, as the European theater of operations was given priority to American forces, this division’s strength was reduced to six (about the size of the initial assault force during the invasion of Normandy). The goal would be to capture southern Taiwan and the mainland Chinese port of Xiamen across the Taiwan Strait.

But this meant conquering a heavily defended 14,000-square-mile island dotted with cities, mountains, and forests. The more they studied the challenge, the more concerned some senior officers became. Just finding enough strength would be a nightmare. “In total, it was believed that a force of 776,913 would be required for Causeway, including all six U.S. Marine Corps divisions, 20 B-29 bomber groups, 41 various bomber squadrons, 40 fighter squadrons, and a large number of naval engineers and logistical support units ” – explains the CMSI report.

The greatest flaw of Operation Causeway was the underestimation of Japanese defenses. Intelligence estimates predicted a garrison of between 90,000 and 170,000 soldiers. In fact, the Japanese had 275,000 soldiers incl conscripted natives from Taiwan. They were supported by 20 squadrons of kamikaze planes and 600 suicide boats.

The Japanese expected the landings to take place in southern Taiwan. They laid 10,000 naval mines, including 5,200 in the Taiwan Strait alone. Given the overwhelming firepower of the Americans, they built complex systems of trenches, bunkers, and tunnels over the beaches and across the island.

“Imperial Japanese and Formosan troops would engage in a long, drawn-out fight in the cities and mountains,” Easton said. “After the end of conventional fighting, a guerrilla campaign was planned. “Taiwan’s defenders were determined to fight to the bitter end, and the defensive position, supplies, and underground bunkers they had were extraordinary.”

How would a U.S. invasion of Taiwan fare? Other battles of the Pacific War provide grim clues. When American troops landed in the Philippines in October 1944, they fought their way through jungles and mountains in a campaign that still did not end with the surrender of Japan in August 1945. In April 1945 invasion on the island of Okinawa, U.S. forces suffered 50,000 casualties in two months against dense fortifications in hilly terrain, as well as from 2,000 kamikaze attacks that sank or damaged hundreds of naval ships.

Ultimately, the Taiwan idea was abandoned. “Militarily, it was absolutely the right decision,” Easton said. “Professional war planners hated the idea of ​​having to fight in Taiwan, and with good reason.”

Lessons for China

Even eighty years after the end of the Japanese occupation, Taiwan’s military is still influenced by Japanese doctrine, such as the importance of strengthening air bases and how to face an amphibious invader armed with enormous air and sea firepower.

Taiwanese forces continue to use Japanese-built facilities, including some bunker complexes. Some Taiwanese officers advocate renovating old beach defenses and preparing for a prolonged guerrilla war, as the Japanese did.

China will face these and even greater challenges as it tries to take over Taiwan today.

“Taiwanese military officers pay close attention to history, especially the history of island warfare, urban warfare and amphibious warfare,” Easton said. “They have all the defensive advantages that the Imperial Japanese enjoyed and even more, thanks to modern weapons and strong American support.”

Michael Peck is a defense writer whose work has appeared in Forbes, Defense News, Foreign Policy magazine and other publications. He holds a master’s degree in political science from Rutgers Univ. Follow him Twitter AND LinkedIn.