‘WHY THE JAPANESE DIDN’T TRY AND INVADE AUSTRALIA IN WORLD WAR 2′

by Andrew Ross.

In late February 1942, the Japanese army and navy discussed an invasion of Australia. Although the navy was enthusiastic, the army put forward a military appreciation which dismissed the idea as far too dangerous.

It recognised that Australian forces were likely to be better armed than the Japanese divisions and more mobile. The appreciation said an invasion would require a minimum of 12 divisions. This force could not be provided from existing resources without weakening Japan’s hold on its conquests, and it might still be defeated by the aggressive Australians defending their homeland. The Japanese army rejected the navy’s suggestion. The idea was never considered seriously again by the Japanese.

Australian scientists, technocrats and industrialists had created so much equipment that Japan could not supply the volumes of its own material to overcome it. Japanese airpower could not redress this imbalance because it had not developed effective close air-to-ground support for its troops and had to face heavy Australian anti-aircraft defence. The Japanese were also aware that Australian strength in fighter aircraft was increasing steadily, and that radars were spread up the east and north coasts of Australia. Thus, Australia’s greatest strategic victory in World War II was achieved by science, technology and secondary industry.

The US naval victory at the Battle of Midway, in early June 1942, removed Japan’s capability to invade Australia by destroying its main aircraft carriers. This made it safe for Australia to begin to transfer military power to fight the Japanese in Australian Papua and New Guinea. Australia had to re-equip its army to cope with the corrosive jungle environment and extremely steep and rugged terrain. The battles took place in terrible conditions, which should have favoured the Japanese defenders. A stalemate was the most likely result, with heavy casualties on both sides, which the Japanese were willing to accept.
The early battles followed this pattern. But Australia had organised its scientific and technical resources far more efficiently than Japan. By mid-1943, Australia had become, for the allies, the centre of research into jungle organisms and jungle-proofing of all weapons and equipment. A flood of new equipment, specially treated clothing and food, and a vastly superior medical support system with Australian-made drugs and antibiotics swung the struggle in the jungle decisively in Australia’s favour.

Japanese battle casualties in the Southwest Pacific inflicted by the Australians were well over 50,000, whereas Australian battle casualties were 14,700. Japanese deaths from disease and starvation in the same area were over 100,000. Australian deaths from the same causes were about 1,000.

At this ratio of 1:3, Australian battle losses were the opposite of the classical ratio for an attacking force encountering a well-prepared defence, in rugged, well-covered terrain. The Australians reversed this loss ratio through better-designed weapons, better communications, better-quality ammunition and flexible battle tactics. Japanese weapons were poorly designed for jungle warfare in equatorial regions, their ammunition and communications were degraded by jungle organisms, and their battle tactics were often inappropriate for the conditions and terrain in which they fought.

The extraordinary imbalance in deaths caused by disease and starvation was a direct consequence of the Japanese army’s lack of logistic and medical support for its troops. Before World War II, Japan had conducted nearly all its campaigns in well-populated and productive environments such as China and Manchuria. These environments were not particularly unhealthy, so it could get away with a rudimentary medical system. Similarly, food could be taken from the local populations, so Japanese forces did not need an elaborate logistic support system.

When Japan began its Kokoda campaign, it needed to sweep away the opposition quickly, before the disease took hold in Japanese troops and they exhausted their rudimentary food supplies. They could not rely on getting food from the sparse local population.

Although it took some time to organise, by early 1943 the Australian logistic system provided good medical support and increasing amounts of food.
The result was devastating because nearly all of Japan’s post-Kokoda campaigns in Southeast Asia were conducted in jungle environments with sparse populations, which dramatically exposed logistic and medical deficiencies.

The impact of Australian science, technology and secondary industry on the survivability of Australian troops can be calculated roughly. Australian forces might have expected a minimum of around 45,000 casualties, given that they were trying to drive the Japanese out of very formidable defensive positions. If the Japanese had been able to prolong their resistance, this would have produced a situation like many World War I campaigns and caused Australian casualties as high as 80,000. The impact on Australia would have been enormous.

Australia’s war economy also provided vast amounts of clothing to hundreds of thousands of American service personnel in the Southwest Pacific. Huge quantities of basic materials for road and base building, as well as armaments, transport and signal equipment, were also supplied. In 1943, Australia supplied 95% of the food for 1,000,000 American servicemen.

In commenting on this wartime support, President Harry Truman wrote in his 1946 report to the US Congress on the Lend-Lease Act, ‘On balance, the contribution made by Australia, a country having a population of about seven millions, approximately equalled that of the United States’.