Diary of a junior Japanese officer describes the appalling circumstances of the Japanese in retreat.
http://www.usssanfrancisco.org/Japanese/genjiru2.htm
yes,the japanese position on guadalcanal was horrible.troops eating bark and grass,wounded and sick left behind to die.Constant air attacks from henderson field aircraft.The japanese did pull off a remarkable evacuation though.the americans had no idea what was going on.In the end the japanese evacuated about 13000 troops,out of 36000 who fought there.The japanese suffered 15000 dead and missing 9000 dead from disease and another 1000 captured compared to about 1600 killed on the american side.
Elsewhere the Japanese refered to Guadacannal as “Starvation Island”.
The failure to win control of the air doomed the men of the 17th Army.
One of many.
The state of Japanese troops east of Timor started to deteriorate from early 1943, largely through reductions in shipping LOC because of Japanese over-extension and steadily increasing Allied reductions in already stretched Japanese shipping capacity.
By 1944 many Japanese troops were virtually marooned in Papau New Guinea and islands to its east, reduced to scavenging from native food gardens and growing their own food and in backwaters left largely alone by the Americans to do so as they (both Japanese and Americans) had little offensive interest.
I have spoken with a few Australian soldiers who served in Papua New Guinea. They were to varying degrees distressed by their part in killing and, in many cases virtually slaughtering, starved and ill Japanese troops who attacked their positions in hopeless onslaughts or who defended Japanese positions with the same starved tenacity first encountered at Gona, Sanananda and Buna at the end of 1942.
While the Japanese worked from a cultural view of obligations starting with the individual through the family up to a religio-mystic obligation to the Emperor, they also displayed a callous disregard for the individual failing to meet group expectations as exemplified by their brutal military training and demands upon the individual.
This led the Japanese to have contempt for Allied individualism, as exemplified by attempts to save individuals at the risk of the group, which was seen as an example of the deficiencies of decadent Western culture which threatened the survival of the group to no purpose when balanced against the loss of an individual.
Yet, in the end, it was the group loyalty attitudes which created Japanese callousness for their own troops which allowed them to be abandoned in betrayal of those supposed loyalties in large outposts east of Timor to be isolated and reduced by the Allies, where the supposedly individualistic Allies would have taken the opposite approach if the positions were reversed and did where possible.