The Japanese operational plans called for six large aircraft carriers of the Japanese combined fleet to sail from Truk and head south of the Solomons and then west into the Coral Sea. Their role was to support and protect the invasion fleet headed for Port Moresby. 

This invasion fleet was to consist of 5,000 marines of the Japanese Special Naval Landing Forces in 12 transports escorted by destroyers and cruisers with one light aircraft carrier to provide air cover. They were scheduled to attack Port Moresby in the first week in May 1942. They were to assemble at Rabaul and sail down through the Louisade Archipelago around the eastern end of New Guinea and attack Port Moresby. This amphibious assault was known as "Operation MO".

The role of the six aircraft carriers was to attack any Allied Naval forces trying to intercept the Japanese Invasion Fleet. Following the invasion of Port Moresby, the six Japanese aircraft carriers were due to head southwards to mount a massive 300 aircraft air-raid on Townsville

On 18 April 1942 Colonel Doolittle launched his daring bombing raid on Tokyo, Yokohama, Kobe and Kyoto using B-25 Mitchell bombers launched from the decks of US aircraft carriers. In fact General Tojo was flying back to Tokyo at the time of Doolitle's daring raid and his aircraft had to take evasive action to avoid an unfamiliar brown twin-engined aircraft which the crew told a worried Tojo was a land-based American Mitchell bomber.

As a result of Doolittle's air raid, the Japanese changed their priorities in readiness for the invasion of Midway. The Japanese knew that the Americans only had four aircraft carriers in the Pacific Ocean. They knew that two of these carriers were used in Doolittle's raid on 18 April. Japanese intelligence knew that USS Lexington was in Pearl Harbor so that left only one aircraft carrier, the Yorktown in the South Pacific. 

Based on this they decided to downgrade the Combined Fleet support for the Port Moresby Invasion to just a Task Force support and at the same time the 300 aircraft air-raid on Townsville was removed from their plans. (Wheh!!!) The Japanese despatched only two aircraft carriers, Zaikaku and Shokaku, and the light carrier Shoho to support the invasion of Port Moresby. The rest of the Japanese fleet would make preparations for the invasion of Midway.

On 25 April 1942, General MacArthur sent a signal from Melbourne stating "Information indicates the assembly in the JAPANESE MANDATES of sea and air forces of at least three aircraft carriers and five 8-inch gun cruisers capable of striking in any direction". Another signal advised in part "Possibility of AIR RAID by carrier based aircraft force against EAST coast of Australia, by 2 May ....."

Australian military commanders were anticipating a possible strike by carrier-borne aircraft along the coast between Brisbane and Townsville somewhere between 28 April and 3 May 1942 co-incident with an invasion landing near Port Moresby.

The Americans intercepted the Japanese aircraft carriers supporting the invasion of Port Moresby in the Coral Sea. This well known naval battle became known as the Battle of the Coral Sea. Because the Allied codebreakers were able to read most of the Japanese Naval radio traffic, Admiral Nimitz was well aware of the Japs plans, he was able to request Admiral Frank Fletcher of the USS Lexington to make a high speed journey from Pearl Harbor in time to attack the Japanese Navy in the Battle of the Coral Sea.


Japanese Air Raids in Australia



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This page first produced 22 October 2000

This page last updated 23 February 2020