If homeostasis has a moral analogue then, cinematically, Part III of the "Human Condition" is its most painful, yet universal in resonance, visual depiction. As Kaji becomes disillusioned with the humanist socialism he so fervently had embraced, the reduction of the human to nothingness concludes this anti-Odyssey towards a forever lost home. Nature's vast indifference is extraordinarily filmed in sparkling shots.
Kaji losing his hold on his ideology - his pacifism and deep commitment to socialist values - is one element of tragedy present in the final part of Kobayashi's epic. But more than that, is an underlying element of absurdity, of Kobayashi's deeply felt belief that being human is being a vehicle of senseless rage. It will appear time and time again - war, murder, desecration - even when it's avoidable.
The final stage of Kobayashi's anti-militarist trilogy is a three-hour slog through intense heat, intense cold, and intense suffering all round. Kaji's morals are worn away, as this poor, bare, forked animal leads his bedraggled troops and a motley gang of refugees through an already lost war and then into a gulag. The early melodrama gives way to a savage indictment of the Japanese military code in its every form.