Why Fighting On WWII's Pacific Front Was Worse Than You Thought

Bracketed by the attack on Pearl Harbor and the nuclear attacks on Hiroshima and Nagasaki, the United States' involvement in the Pacific Theater of World War II presented one of the biggest combat and logistical challenges the country had ever seen. U.S. forces would have to fight enormous distances from home, on islands with unfamiliar climates and harsh terrain, and against an entrenched and merciless foe. These fighting men would have to be fed, armed, cared for when wounded, and returned home (alive or dead) by a vast and sophisticated infrastructure and supply network encompassing much of the largest ocean on the planet.

This sounds unpleasant and difficult, and indeed it was. While none of the active theaters of the war was a cakewalk, the Pacific Theater presented specific challenges due to the climate, terrain, and Japanese war strategies. Ultimately, the United States won the war the way most wars have been won: by having more fighters willing and able to advance, no matter the cost, than their enemy had, despite suicide attacks, disease, the unpredictability of nature, and the enormity of mounting invasions across an ocean.

Late in the war, the crew of the USS Indianapolis suffered one of the most unexpected and frightening hazards of the Pacific war when, after they evacuated their sinking ship, they were attacked by sharks. On July 30, 1945, two torpedoes launched by a Japanese submarine crippled the Indianapolis, which sank in a mere 12 minutes, taking just under 300 of its crew with it.

Despite having little time to do so, 900 men had managed to evacuate into the waters of the Pacific. Over the four days and five nights they waited in the sea for rescue, the number of survivors was whittled to just 316. While many died by other causes — in addition to the obvious hazards of the open ocean, many had been wounded in the attack — the shark attacks have become the most infamous. There's no accounting for how many men died from these predators, but survivor accounts by those who witnessed such attacks make harrowing reading, with survivors reporting kicking the sharks to dissuade them.

The Japanese had, unfortunately for them, hit the Indianapolis too late. The ship was returning from a very important mission when it was struck, having just delivered nuclear weapon parts to scientists preparing the weapons on the island of Tinian. The men of the Indianapolis would be avenged many times over with the bombings of Hiroshima and Nagasaki, which occurred just a few days after the survivors were rescued.

By October 1944, the loss of many of the islands that Japan had until recently occupied meant Allied bombers had better and better access to Japan's skies, and Japan correctly feared that an invasion of its home islands was coming. To make further American advances against Japan seem too costly, the Japanese turned to suicide bombers who would slam their planes into Allied ships to damage or destroy them. They were called "tokkōtai," an abbreviation of the Japanese for "special attack units," but most of the world remembers these Japanese pilots as kamikazes.

Japan was running short on most of the materials they needed to continue the war, but they still had planes and pilots. Beginning in October 1944 with a leading-by-example attack by Rear Admiral Masafumi Arima against the carrier USS Franklin, the Japanese armed forces would rely more and more on these attacks as the war ground to its end, even to the extent of building cheap one-way planes especially for this purpose. And it wasn't just planes: Small boats and even human-driven torpedoes were used in one-way sorties against U.S. assets.

Kamikaze attacks were hard to counter, but the U.S. forces stayed them somewhat through the use of radar-equipped pilot boats accompanying warships, advances in anti-aircraft guns, and a renewed focus on strikes against Japanese airfields. One of the main architects of the plan, Vice Admiral Matome Ugaki, died in one of the last kamikaze attacks the day of the emperor's surrender address.

Like most countries at war, Japan ran a system of prison camps to detain enemy nationals caught up in their conquests as well as captured soldiers. While conditions varied from camp to camp, a general Japanese contempt for anyone — Japanese or foreign — who had surrendered, and the Japanese refusal to abide by the 1929 Geneva Convention on rules of war, meant that conditions for the imprisoned were seldom rosy.

Prisoners were often transported from outlying areas to Japan or one of the industrialized areas it controlled, like Korea or Taiwan, in order to be forced to work for the Japanese war effort, with the secondary effect that they were far from any potential rescue as Allied armies advanced. As Japan did not mark prisoner transport ships, many drowned as a result of Allied attacks on what appeared to be legitimate targets; many would also die in air raids on Japanese cities. Those who arrived were subject to family separation (for civilians in captured territory), segregation by sex, and malnutrition. Then there was the forced labor, harsh punishments for real or perceived infractions, and abuse that sent the death rate for internees above 10 percent of all those taken into the Japanese POW system, with a higher rate for foreign soldiers.

A particularly illustrative example of Japanese forces' cruelty to those they captured is the Bataan Death March. The Japanese had begun their assault on the U.S.-held Philippines the day of the Pearl Harbor attack, and the underprepared and underprovisioned U.S. and Philippine troops defending Manila had fallen back to the outlying Bataan Peninsula. After a 99-day siege, they were taken by Japanese forces.

The Japanese themselves were unprepared for the surrender of 76,000 or so men, and so they began to force the prisoners, as well as others from across the captured island of Luzon, to march to a rail depot for transport. Each day of the march began with the Japanese captors forcing the prisoners to stand in the tropical sun to weary them. They were then forced to advance along the roads, with the guards beating the hesitant to harry them along. Stragglers were killed by shooting, bayoneting, or beheading, as was anyone accepting help from a sympathetic local, who also would have faced a similar fate. Some soldiers were forced to dig improvised graves for their fellows along the route.

At the end of the six-day march, the prisoners were stuffed into overcrowded boxcars and sent to an improvised POW camp at a captured U.S. installation, where they fared little better. Counting combined deaths from the march and the conditions at Camp O'Donnell, the overall death rate seems to have been over 30% among American servicemen and potentially higher for the Philippine troops.

Far from home and in unfamiliar tropical conditions, deployed soldiers were at risk of exotic diseases they had no immunity to, as well as the more familiar ailments that show up when people try to practice hygiene under duress. Disease remained a major killer of servicemen in the Pacific: In the Southwest Pacific subtheater, home to relatively large and heavily forested islands like New Guinea, the Philippines, and Borneo, deaths from disease more than doubled those from battle.

Contaminated food or water could spread the common but still very dangerous dysentery, as well as cholera and some forms of hepatitis. Mosquitoes, in addition to general annoyance, transmitted malaria, a particularly grave concern given that Japan controlled the world's major source of the then-standard antimalarial drug quinine through its capture of Java in the Dutch East Indies. (Quinine would later be laboratory-made in 1944, but that's a couple of rough years of malaria risk for Allied troops.) Dengue, a viral fever characterized by intense body pain that also comes from mosquito bites, was also a risk. Other little biting pests carried scrub typhus, which can cause hemorrhaging and hallucinations, and leishmaniasis, a parasite whose symptoms of boils and sores earned it the grimly playful name "Jericho buttons."

Additionally, when soldiers on the rainy islands couldn't stay dry, they could develop skin conditions from the constant damp that went under the catchall name "jungle rot." Treatment for such conditions includes cleaning and bandaging the area, then staying dry and avoiding sweating — an optimistic guideline in battle in New Guinea.

Malnutrition is a serious complicating factor in wartime conditions, both for the obvious reason that it eventually leads to death and because an underfed fighting force is significantly more vulnerable. Weak men can't fight as well, and disease takes a greater toll on people who are already operating at a deficit due to poor and/or inadequate nutrition. It takes a lot of calories to successfully fight a disease like malaria, for example.

Soldiers fighting in the Pacific were especially prone to a dangerous deficiency of Vitamin B1 called beriberi, which can cause muscle weakness, nerve damage, and cardiac insufficiency, ultimately leading to death if unaddressed. Beriberi is easy to avoid with the varied diet of protein-rich foods that most Westerners enjoy, but it becomes an issue when people have to subsist on simple carbohydrates, such as the white rice that was the ration for many Japanese forces and their prisoners.

Due to their supply networks and the enormous amount of food the American homeland could produce, hunger was only a serious concern for American troops under certain severe circumstances, such as the desperate times around the fall of the Philippines or for those imprisoned by Japanese forces. Japanese forces suffered far more from a dearth of nutrition since their rocky Home Islands were not able to produce much surplus, and American submarines gutted their shipping, including food imports and transport, as the war went on. The grimmest estimates posit that 60% of Japanese combat deaths were from starvation or malnutrition.

In its most stripped-down literal meaning, "banzai" is a traditional greeting for the Japanese emperor that means "ten thousand years" (the preceding "may you live ..." is implied). From that relatively arcane usage, it became a Japanese war cry, and from there came to describe a savage human-wave attack.

Banzai attacks were particularly deployed in the Japanese attempt to hold Saipan. The fall of Saipan in the Mariana Islands would mean that one of Japan's most important internal defense perimeters had been punctured: Saipan was close enough to Japan that American bombers could use it to wallop Tokyo effectively at will. The Marines landed on Saipan on June 15, 1944, and in a bloody battle of attrition cleared much of the island over the next three weeks. As the battle moved toward its end, just over 4,000 Japanese troops and some civilians found themselves with their backs to the sea and under a commander who refused to surrender.

The Japanese defenders had taken a vow to take seven American lives each before their deaths, and they were running out of chances. So on the night of July 6-7, they pounded what beer and sake they had, and then in the wee hours of the morning burst out of their encampment screaming and brandishing their swords. The Japanese threw themselves at the American forces with no hope of victory but the assurance of carnage. After 12 hours of ferocious fighting, effectively all the Japanese defenders lay dead. They had taken over 400 Americans with them.

New Guinea is the second-largest island in the world (behind Greenland), mountainous across its entire, forested length, and with annual rainfall that totals over 300 inches in some places. It is a land of amazing cultural and natural diversity, being home to some of the planet's great wonders, but not somewhere you'd want to, say, walk across while fighting the Japanese.

The terrain of the islands across which Allied forces had to fight was an enemy almost as fearsome as the Japanese army. New Guinea was the largest and perhaps least hospitable, at least by the standards of American doughboys used to things like seasons and plains, but the challenges presented by the lush, rocky terrain were duplicated on many of the islands that lay between Allied servicemen and Japan.

But if the Japanese were fighting somewhere, the Allies had to as well. New Guinea stood between the Japanese empire and the important Allied stronghold of Australia, and if the Japanese captured Port Moresby, the island's capital on its south coast, they would pose an unacceptable threat to Australia and its shipping. Back-and-forth fighting in the jungle claimed lives even as it camouflaged both sides' maneuvers. Disease was rife, supply was uneven at best, and rain was nearly constant, but it was even worse for the Japanese than the Allies: The ratio of dead in New Guinea seems to have been an incredible 23 Japanese killed for every Allied death. 

During World War II, the rule of thumb was that soldiers could withstand somewhere between 60 and 240 days on the front line before they cracked. That might sound like a wide range, and it is, but situations on the front could vary nearly as much as the individuals placed in them. For example, a soldier was "lucky" to remain coherent after 45 days on the front during the invasion of Normandy. The armed services tried to screen out those it thought were mentally weak, but their predictive abilities often failed, and even some of the most elite fighters succumbed to stress and exhibited symptoms like tremors, amnesia, and — unsurprisingly — enormous sensitivity to sudden loud sounds. Commanders had to acknowledge that every fighter had a breaking point that couldn't really be predicted.

Psychological strain could be even worse for those taken prisoner. The control exerted by captors, abuse, frequent fear of torture or death, and loss of agency that mark the experience of wartime imprisonment are connected with worse aftereffects even post-liberation. A study conducted 40 years after the war's end noted that while combat veterans with and without POW experience had similar rates of anxiety and depression in later years, the former POWs were almost three times more likely to be diagnosed with post-traumatic stress disorder over their lifetimes.

Americans of Japanese descent were in a particularly complex situation during World War II. While most were loyal to the United States, that didn't stop the U.S. government from forcing most of them into internment camps, even those who were natural-born citizens, to wait out the war under guard. Despite this insult, a significant number of Japanese Americans of fighting age served in the U.S. armed forces during the war, choosing Uncle Sam over the emperor and contributing to Japan's defeat. Indeed, the first Japanese POW captured by the Americans, who was taken at Pearl Harbor, was collared by the Japanese American national guardsman David Akui.

People of Japanese descent had a couple of obvious roles in the war effort beyond the more common assignments. They could spy or teach Japanese, and some used their command of the language to prepare psychological warfare gambits, such as leaflets appealing to Japanese forces to surrender. Japanese Americans would also form mostly-Japanese units like the 442nd Regimental Combat Team, which would gather an astonishing record of decorations and medals for its valor in battle in Europe. 

Japan invested heavily in biological warfare research before and during World War II. The notorious Unit 731 experimented freely on human beings, both civilians and POWs, replicating on a smaller but no less gruesome scale the horrors of the Nazi experiments in Europe. While Japan's actual germ warfare attacks were only deployed against China, where they intentionally seeded plague, there were several plans and attempts to use germs against Allied forces in the Pacific, and the Allied brass knew about it.

A handful of twists of fate saved Allied servicemen from being added to the grim tally of Unit 731's human guinea pigs. Plans to infect the besieged American and Philippine forces at Bataan were rendered irrelevant by the surrender. Gliders intended to hit troops on Iwo Jima with plague bacilli never successfully reached the facilities to receive their fatal payload. There were even Japanese plans to attack the U.S. homeland with floating bombs armed with biological agents, an operation poetically labeled "Cherry Blossoms at Night," but this plan suffered from the worst possible scheduling: It was set to be enacted in late September 1945, but by then, Japan had been knocked out of the war.

Part of the justification for the deployment of atomic weapons against Hiroshima and Nagasaki was that the Japanese were such dogged opponents that invading forces would have to fight for every inch, not just of the Japanese home islands, but also perhaps of the still-significant territory Japan controlled in mainland Asia. Japanese civilians, including women and children, had been given defense training. While it's impossible to say what would have happened, this argument was based on Allied armies' experiences of Japanese fighters as being very reluctant to retreat or surrender.

Iwo Jima became a famous example of Japan's determination not to lose easily. The island of Iwo Jima is tiny, a mere 8 square miles in surface area. Using natural caves and manmade reinforcements, the Japanese made it a near-uncrackable nut that took nearly a solid month and 6,800 U.S. Marines' lives to overrun. Some 18,500 of the 21,000 Japanese defenders were killed, an astonishing ratio that made Japanese relentlessness a standard assumption in U.S. planning and public memory of the war.

It wasn't just the Japanese servicemen who were so difficult to outfight. On Saipan, civilians had been impressed by the commander to reinforce his troops for the final banzai attack; after it failed, an estimated 1,000 Japanese civilians on the island threw themselves from cliffs rather than accept captivity.