I am glad that you notice it! I am using a Japanese pentatonic scale called "IN" Scale.
Pentatonic scale has a weird phenomenon that even you simply play the notes by going up or down the scale it will still sound nice as long as they are in the same key.
Viewing post in Night Cherry Blossom jam comments
Basically, in C key: C D E♭ G A♭ C
This is the link in case you are interested :)
https://en.wikipedia.org/wiki/In_scale