Chibi Maruko-chan was a slice-of-life manga about a little girl. Of the 1000+ TV anime episodes of it, I only watched a few of them and am not a fan. I never liked Chibi Maruko-chan because my impression of her (which could be wrong) is that she always causes troubles by being naughty and/or disobedient.
Chibi Maruko-chan: A Boy From Italy (Blu-ray release 2016-8-17), the third movie in the series, does not require watching previous stuff first. The story is simple: six foreign students come to visit, and one of them – the Italian boy stays with Maruko-chan’s family. Maruko-chan initially does not want to be bothered, but of course their friendship develops. Another plot thread is about the Italian boy’s search of the Japanese friends of his recently passed away grandfather. Surprisingly it provides an emotional core and brings depth to the movie, which would otherwise be just a friendship movie. Even without a villain, the movie is not dull at all. I also like that Maruko-chan does what she is supposed to do in this movie, instead of screwing things up.