I was really surprised when I found out that one of my favorite songs, プラネタリウム (Planetarium), from the 花より男子 (Hana Yori Dango) soundtrack by 大塚 愛 (Ai Otsuka) was accused of being plagiarized. More to add to my surprise was that it was accused of being ripped off from another of my favorites, 素敵だね (Suteki da ne) – the theme song from the Final Fantasy X game developed by Square Enix, sung by 中野 律紀 (Nakano Ritsuki – more commonly known as Rikki).
The two songs have very similar melodies and lyrics. The videos also share similarities. Although it is not clear if this was intentional, though I seriously doubt after watching both the music videos that it could be unintentional, it is commonly believed that Ai Otsuka used this song as a homage to Rikki.
Here is Ai Otsuka’s Planetarium video being compared with Rikki’s video