Which was the name of this Rurouni Kenshin song? I remember the song in the begining of this video was from Rurouni Kenshin. But I can't remember its name. Which is the name of that song?

https://www.youtube.com/watch?v=JsOJJlLd8YY
The song in your video is the third ending in the series named 'Heart of Sword'.

You can find it here