The Japanese were aware, via signals intelligence, of the large-scale movement of Allied forces in the South Pacific area but concluded that the Allies were reinforcing Australia and perhaps Port Moresby in New Guinea.
Japanerne havde aflyttet den allierede radiotrafik, og var klar over at en storstilet overførsel af allierede styrker fandt sted i det sydlige Stillehav, men konkluderede, at de allierede var i færd med at forstærke Australien og muligvis Port Moresby på Ny Guinea.