Australia–Japan Research Project at the Australian War Memorial
The human face of war
Papua prologue

After the setbacks at the naval battles of the Coral Sea and Midway in May and June 1942, the Japanese planned to secure Port Moresby to protect their base at Rabaul, to enable an expansion of operations to the north of Australia, and to blockade the supply routes in the region. The operation was not, however, based in sound research, especially concerning the stability of lines of communications and logistical support.

The decision was taken to undertake the campaign regardless of these difficulties. The offensive on Port Moresby commenced with the landing of the Yokoyama Advance Force at Buna and Gona on 21 July. Later, the South Seas Force, based on the 144th Infantry Regiment, landed with the intention of invading Port Moresby over the Owen Stanley Range via the village of Kokoda.