Apparently there is a chinese anime
movie series, "Window of Heart" (?) (心灵之窗), that copied some parts of "5 Centimeters per Second".
Links with some comparisons:
http://en.gigazine.net/index.php?/ne...902_china_5cm/
http://www.tianya.cn/publicforum/con.../1601020.shtml
ETA: This was posted also on ANN:
http://www.animenewsnetwork.com/news...5cm-per-second