'1942, Australia’s greatest peril'

The weight of evidence showing that invasion of Australia was seriously contemplated is considerable. It is in Japan’s official war history Senshi Sosho, minutes of meetings between the Navy and the Army, in memoirs and diaries of Japanese officers, in official interviews and post-war interrogations conducted with participants, and in the writings of historians, both Japanese and Western. A quick selection from an extensive list of history books:

• Admiral Yamamoto’s biographer, Hiroyuki Agawa, The Reluctant Admiral, (Kodansha): “It was the first - the attack on Australia - that was most enthusiastically advocated by the operations division of the Naval General Staff.”
• Yamamoto’s air commander Mitsuo Fuchida, in Midway (US Naval Institute): “Following the easy conquest of the Bismarcks in January, the most aggressive proponents of the Australia-first concept started advocating outright occupation of key areas in Australia.”
• Pulitzer Prize winning author John Toland in The Rising Sun (Penguin): “The Navy envisaged invasion of Australia itself with five Army divisions.”
• Australian war historian Gavin Long, The Six Years War (The Australian War Memorial & the Australian Govt Publishing Service): “And soon naval leaders were advocating two more ambitious ventures: invasion of Australia and a thrust towards Hawaii.”

Soon after the Japanese attack on Pearl Harbor, the commander in chief Combined Fleet, Admiral Isoroku Yamamoto, had his chief of staff Admiral Matome Ugaki examine Japan’s “second stage” offensives. Initially Yamamoto insisted that Japan must follow through by aggressive action in all directions to keep the Americans off balance and allow Japan to expand the new perimeter until Washington sued for peace.

Yamamoto told Ugaki, according to the war history series Senshi sosho, that he had three targets in mind: India, Australia and Hawaii. Of the three Yamamoto counted Hawaii as the most important, because of the strategic threat the Pacific base and it’s as yet untouched carrier fleet. Australia was included in Yamamoto’s initial invasion plans, according to John J. Stephan, Hawaii Under the Rising Sun (University of Hawaii Press), because the commander-in-chief wanted a bold strategy which he called happo yabure, or “strike on all sides”.

After much study, Ugaki, in late January and early February, came down favour capturing Australia’s north, among other landings. Ugaki’s operational planners in Combined Fleet embraced invading northern Australia, along with other strategic points. They submitted a plan to Navy General Staff a list of priorities which included the comment: “Port Darwin must be taken.”

Naval General Staff soon agreed with Yamamoto’s Combined Fleet. Admiral Nobutake Kondo, commander of the attack force on Malaya and the Dutch East Indies, was a former chief of staff of the Combined Fleet. He prepared a proposal for Yamamoto. Kondo saw Japan as having two planning options: one was an operation to take India and the other, an operation to capture Australia.

The Australia operation … could be regarded as part of our main operation against America and also would have a rich chance of taking hold of American task forces.

Vice admiral Shigeyoshi Inoue, a moderate, was the commander of the Japanese Fourth Fleet. Inoue and his staff officers aboard the cruiser Kashima called for Japanese expansion in the Solomons-New Guinea area, as the necessary first steps required for landings on the Australian mainland.

Another admiral’s plan came to light during table manoeuvres aboard Yamamoto’s flagship, the Yamato, anchored on the Inland Sea. It came from a close confidant of Yamamoto, Rear Admiral Tamon Yamaguchi, commander of the Second Carrier Division.

Between February 20 and 23 Yamaguchi distributed copies of a blueprint invasion plan proposing widespread invasions across the Indian and Pacific oceans starting from May 1942. There would be an invasion of Ceylon in May. During June and July 1942 landings would be made on Fiji, Samoa, New Caledonia, New Zealand and northern Australia.

But Yamamoto now was becoming interested in a new plan to take the atolls of Midway to draw out the US Pacific fleet for a decisive battle. Midway would be a precursor to an invasion of Hawaii, and, if successful, would have meant follow-up invasions of Australia, New Zealand and adjacent islands.

General Tomoyuki Yamashita, who had captured Singapore, was imprisoned near Manila, awaiting trial as a war criminal in 1945, when he spoke of his wartime plans for invading Australia, to quote author John Deane Potter: