The Prussian military theorist Carl von Clausewitz said that artillery is the weapon an army can least do without...
The Australians along the Kokoda track did entirely without artillery except for a few days from 21 September 1942. When the Japanese were on Ioribaiwa Ridge, at the limit of their advance, two 25lb guns of 14th Field Regiment were dragged up to Owers' Corner from where they were able to fire on the enemy.
The Japanese experience of war in China in the 1930s had taught them that in remote road-less regions the only artillery they would have was what they carried with them. On first landing in Papua they had 17 artillery pieces. These were of three types; 75mm mountain guns, 70mm infantry guns and 37mm guns which could fire an anti-tank or an anti-personnel round. All three could be taken apart and carried by horse or man. When the Japanese advanced into the Owen Stanley Range the carrying of the guns and their ammunition had to be done by men alone. One fifth of their force was needed to shoulder the burden of the disassembled guns and several thousand rounds of ammunition.
The great labour involved was, in the first half of the campaign, rewarded by victory in battle. To have no artillery, when the enemy has it, is to be disadvantaged like a boxer who finds his opponent has a much longer reach than him. The Japanese artillery had several times the range of any Australian weapon but in jungle war the gunners usually cannot see the target. This problem was solved by forward observers. These men advanced with their infantry until they could see the Australians then, by field telephone, directed the fire of their artillery on to the target.
On the last day at Isurava, six Japanese guns were engaged and at Ioribaiwa there were eight, including their three most powerful ones, 75mm mountain guns. The greatest concentration of Japanese guns during the Kokoda phase of the fighting in Papua was at Oivi-Gorari where 13 were in action. In the disaster that overtook the Japanese there, all were lost.