Astonishingly misunderstood!

Rating: 10/10 (4 April 2019)

Oddly enough, Grave of the Fireflies is not actually a story about war. Yes, it's set in wartime and the plot revolves around the kinds of terrible things that happen in war. However, at it's most basic level, this is a story about sin and redemption. Even so, if all you get out of Grave of the Fireflies is that war makes you sad, that's okay. I hope, with this review, to help people understand the much deeper meaning of Grave of the Fireflies.
Spoiler Alert
Aside from the opening scene, which I'll get to later, the movie isn't particularly noteworthy until the children's mother is injured in a fire bombing and is taken to a makeshift hospital in the school. Up to that point the children are just children and there's really nothing special about their lives other than they happen to be living in Japan during the war.
The scene where Setsuko is playing in the sandbox at the school and Seita tells her to watch him while he jumps up on the arm bar and starts spinning around on it is the turning point in the film. After that pivotal scene, Seita begins to make all of the poor decisions that ultimately lead to the children's deaths.
Since the film is animated to highlight the perspective of the children, it's important that Seita's love for his sister is shown throughout the film. I think it tends to make people ignore what's really going on though. We're supposed to be sympathetic about a brothers love for his little sister, but the fact remains that even though Seita believes he is doing things because he loves his sister, he compounds every poor decision he makes by refusing to accept his failure to protect her.
After their mothers death Seita's attitude changes dramatically. He begins to lie to his aunt and doesn't work. When she sells their mothers kimonos. Seita accuses her of cheating him out of food. He eventually alienates himself from the only family he has. He leaves the home and becomes a thief to feed himself and his sister. When he can't steal enough food he takes advantage of the air raids and even cheers the bombers as they fly over because the bombing made it easier for him to steal food and kimonos. Even when his sister is sick from malnutrition and he's told to swallow his pride and go home because the rationing has made it impossible to live outside the system, he refuses to go home and become a productive part of society.
Finally, when he withdraws money from his dead mothers savings to buy food, it's too late. Up until the point where it's just too late to change their fates, the children could have been saved at any time if Seita had simply chosen to act responsibly.
There is a bit of story between Setsuko's death at the end of the film and Seita's death at the beginning. The war is over. Whatever happens in the missing time, it's clear that Seita was unable to find redemption in post-war reconstruction. We know this because he dies of starvation as an outcast from society in the middle of Kobe train station. His spirit has been broken by his own sense of guilt. In the opening scene of the film he is given life saving food that he cannot bring himself to eat because he believes he deserves to die for his sins.
The movie ends with a touching scene of a healthy looking, yet obviously dead Seita sitting on the hill above Kobe, as Setsuko runs happily to meet him. She falls asleep in his lap as they look at modern Kobe in the distance. Oddly, the two people actually killed by the war, the children's parents, are nowhere to be found. They have nothing to do with Seita's guilt and are of no consequence to him as he watches over his sister throughout time. The scene is not a joyous reunion in which the children get to live happily ever afterlife. It's Seita's penance.
The cause of every relevant tragedy in Grave of the Fireflies is not war, but pride. Every terrible thing that happens to the children after the death of their mother is the result of Seita's stubborn refusal to do the right thing. This is the real tragedy, not the war in which the events take place.