To suffer the misfortunes of the ordinary recruit at the hands of the military clique, to place himself in harm’s way without the prerogatives of the officer class—the class that had led Japan into the Pacific War—was Kobayashi’s means of protesting against the war itself. That war, Kobayashi has said simply, was “the culmination of human evil.”...
Kobayashi had been indignant that, at the end of the war, soldiers and low-ranking officers were often punished cruelly, while many of those directly responsible for the crimes escaped censure. - Criterion
Masaki Kobayashi was very critical of the samurai code Bushidō (Harakiri) and how it was still used by the Japanese military (The Human Condition Trilogy).
I couldn't find any pictures of Masaki Kobayashi's earlier films.