Well, if you're accepting anime, then I suppose Utawawerumono fits the bill... I hesitate to recommend it though, because it's not all that great. It's only about average.
And to some extent, Open Sesame has a memory problem. More specifically, one particular portion of the main character's past - which includes a girl he's meeting again now - has been blocked off. But the manga as a whole doesn't focus too much on the memory problem - it's more of a slice of life romance