Beautiful example of "Oriental Perspective"!
One of the first things my Sumi-e Sensei taught me was that, (due to the often-hazy atmosphere) Japanese artists show receding distance, not so much as geometric diminishing-size perspective -- but as ever-increasing faintness or lighter tone or blurriness with distance:
TXnMA
Are you in the sumi-e society?
Beautiful and this has always interested me too. To me, distant hills and mountains, turning bluish in the distance, are almost my favorite scenery.