I (mixed Belgian-Central African) lived in Italy for a year and a half and had only one semi-racist occurence happen (this women who I asked the time for thought I wanted to sell her something

)
Obviously the fact I learned Italian helped, a lot of looks or whatever might be wrongly considered as racist if you don't really know the culture and the language. They can also talk /answer to you in a manner that some might consider rude/aggressive (and thus "racist" if you're another colour) or that they're "testing" you but after a while you realize they actually do that between themselves too.
Now obviously there's racism there (especially in the North, shyt some of them are "racist" towards Southern Italians) but I've been to Italy countless times since I left and nothing noteworthy ever happened. Again, speaking the language helps a lot obviously. As in much of Europe now, it's worse if you look Arab/North African/Muslim. Or Roma/Gypsy. There's still a lot of actual ignorance in the sense that Black people in Italy is very recent (like mainly since the 90s) so a lot, well, just don't know much about Black people, only what the bullshyt Italian media (which is really terrible) show them, and movies.
And in general if you come from the US you're likey to be seen first as an American, second as a Black person.
Anyways I've never been to Japan but you can't go wrong with Italy, culture, scenery, food are great. Be advised that the "South" of Italy (which really is Rome downwards) is often chaotic in terms of organization, public transportation (once had a train delayed...for 24 hours

).
Obviously the usual suspects are amazing (Venice, Florence, Rome...) but it's well worth going to smaller towns (Lucca -close to Florence-, Perugia -nice jazz festival in July I think-, Bologna...). Italy is very decentralized historically (I think it's only been unified for a little more than a century or so) so cities have very strong local identities. Check out the countryside too. Tuscany, Marche - a region that is off the usual tourist routes - Emilia-Romagna, and then off course Sicily (from the regions that I actually saw). From my limited experience (been there twice, but each time for like only 2 days) Milan ain't really all that, very industrial. Turin also wasn't that great, but was also there for a couple days only.