By some quirk of fate, I was actually in Yokohama when I watched this film. From up on Poppy Hill is set in the sixties, but Yamashita Park and the Marine Tower are still recognizable parts of the landscape. Like all Studio Ghibli productions, it is beautifully animated. Magical, even though it is one of the few Ghibli films which is set in a real place and time.
A bit like Arrietty, the story is slight, and unfolds at its own pace. It has some weak elements, however. The central mystery – are they or aren't they siblings? – is rather unbelievably melodramatic, as one of the characters admits. Perhaps baby-switching was a common phenomenon during and after the Korean war. Even if it was, I don't think the film dealt with the repercussions that creates particularly well. It is at its best when it explores the daily life, in school and at home, of the protagonist Umi. She is perfectly charming, and in her own quiet way, one of the most inspiring heroines the Ghibli production house has created. Which is saying something.