Few years ago, my wife and I were in the loop of Miyazaki and Studio Ghibli movies. We were also interested in movies that portrait the immediate aftermath of WW2 in Japan from a common people point of view (we had finished Sun of Sokurov and wanted more).
Merging these two interests we found The Grave of the Fireflies.
It's an outstanding movie and I am sure it will move you deeply. It's the kind of movie you love, that you adore, that you admire with all yourself, but the kind you will never watch a second time. No way. The story is beautiful, it's sweet, but it's harsh. My wife was unable to stop sobbing and hated (and thanked) me for having her watch it, so beware of what expects you. Understand it is an extremely sweet tale of love between a brother and a sister in the war (and after war) times of a thriving and then destroyed Japan. It is based on real events. I use the plural because stories like this one, well... were common. Thinking about that, realizing this simple fact will bring you more sadness.
I am avoiding giving you more details, there is no point and once you will watch I guess you will understand why the details of the story, meanwhile fundamental, are not important. Just few more things IMDB gives 8.6 (here) and I obviously agree. It was made back in 1988 by Isao Takahata. The comments on IMDB are classic for a movie that either you love or hate, either 10 or 1, but in this case the latter is because the expectations were for a cartoon, not for a movie.
I give: 
For everyone?
It is not for everyone. If you expect a Disney-like cartoon, forget it. It's a movie, animated but it is a movie. If you expect a Miyazaki-style tale instead, you will be disappointed but you will find something of it.
Read it and let me know. No, not here, or rather not yet... I will find a
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