海角七号 - 情书

I changed upon this song at a website. The movie 海角七号 is a hit in taiwan and getting numerous good reviews. I have not watch it yet and no plans to do so. But this song in the movie OST, actually it is the movie main theme song, but 填上了词.
This is the original by 范逸臣。

The below extract of the lyrics very nice

一封封 情书穿越缓慢的时空
代替我 来不及说的含情脉脉
我相信 离开终究会有始有终
有一天 我将能为你描写彩虹

And I found the score ! It seems like a C# major song ... C#,Eb,F,F#,G#,A#,C,C#.