From mid-November 1942 to the end of January 1943 the Australians and the Americans reduced the Japanese base in the Gona-Buna-Sanananda area. Called the Battle of Buna-Gona this three month struggle had the characteristics of a siege...
A siege is an attempt to capture a fortress. In ancient times this was often a walled city but in the modern era, with the rise of powerful artillery easily capable of knocking down walls, the ramparts have been replaced by trenches and bunkers.
All the factors that played a part in a typical siege can be seen at Buna-Gona: The attacker attempts to storm the fortress immediately on arrival. If this fails, as it did at Buna-Gona, a siege results. The objective is surrounded, preventing the escape of the defenders and their reinforcement or resupply. A siege can be a drawn out process, if starving the defenders is the objective or if the defences are too strong to assault, but often the low level of operations will be punctuated by a number of small engagements when key parts of the defences are captured bit by bit. Another classic problem of siege warfare which appeared at Buna-Gona was disease. With large numbers of soldiers in one location for several months there is a high probability that sickness, afflicting both attacker and defender, can decide the outcome.
The Japanese defences at Buna-Gona were in four parts. What might be termed the citadel was at Sanananda. It was covered by three outworks, the defences at Gona and Buna on its flanks and a third inland to its front. The Allies approached the coast in mid November and attempted a coup de main - a swift attack relying on speed and surprise. Greatly underestimating the strength of the defences they were repulsed. Realising a prolonged effort would be required they cut the landward approaches to the fortress and brought up reinforcements and artillery to bombard the defenders. Air bombardment was also used.
A difficulty was that the Allies did not control the sea. Allied aircraft severely curtailed, but did not stop, Japanese efforts to resupply the garrison. In December the Japanese attempted a relief - when the side defending sends a force in an attempt to reopen a supply line to the besieged. Landing on the coast north of Gona the Japanese did get supplies and reinforcements to the besieged but the higher purpose of the operation, to maintain a permanent corridor for resupply, was not achieved. Another classic operation of siege warfare practiced at Buna-Gona was that the defenders attempted to sally and destroy the artillery of the attackers. Special units were formed by the Japanese for this purpose.
In early December the Australians captured the northernmost outwork of the defences at Gona. The Americans were unsuccessful at Buna until Australian reinforcements arrived there in late December. The last of the outworks, in front of Sanananda, was reduced in mid-January. The Allies began to consider that the remaining Japanese at Sanananda could be left to perish from starvation and disease. The element of attrition is a strong one in a siege. Buna-Gona was a hyperendemic malarial region and the besiegers lost as many thousands of casualties to disease as did the defenders.
Aware that the fall of all the secondary positions heralded the eventual fall of Sanananda the Japanese there were ordered to make a breakout and to escape north along the coast. Some succeeded and by 21 January all organised Japanese resistance in Papua ceased.