Suzume...Hyoutan Suzume (1959).
It's a really great movie...well, maybe it's a great movie, I don't understand Japanese too well and nobody ever bothered to translate it, but yeah, it's probably a great movie. I got the impression that the narrative was some really high brow, deep thought, complex feelings kind of stuff, but it thankfully wasn't too heavy on the piano, so it was nice to see Makoto Shinkai finally branch out a little from his usual fare. I was a little miffed that @Sarex wouldn't recommend something like this to me, but it is rare that we agree on something, so I suppose he probably was just exercising an understandable level of caution. Luckily, there was no need for that here: when you've got such cutting edge art and animation like the above, I don't think you really need anything else anyways, .