It's funny what you find on the internet. Specifically, videos which feature songs in tutorials. And it's easy to understand this song, as there are few words that are sung.
Casker - Fragile Days
Earlier stated, I found this song on a video (yes, I do watch a lot of strange videos when I am bored). But what grabs my attention would be the music played in the background. This is a relaxing sound that you can listen to just about anywhere, may it be a café, a lounge, a stroll in the park - it sets the mood. Although it is by a Korean band, the words that are sung are peaceful and don't distract the rest of the laid back, up-tempo Jazz. Who they are, I am not sure. But I am glad that Vloggers choose good music that open up my library to endless options.