Okay kiddo, so there are these things called "tang records" which are kind of like really old school music recordings from a long time ago in China. And some of the best ones come from the western regions of China, which is a place far away from where most people in China live.
The reason these tang records are so special is because they give us a peek into what life was like a long, long time ago. You know how we have music today that tells us what people are feeling and what life is like? Well, these tang records were like that for people back then. They would listen to them and hear stories and songs about everything from love to war to daily life.
And the western regions of China were especially interesting because they had a lot of trade and interaction with other countries like India and Persia. So the tang records from there often have a unique blend of different cultures and influences.
Even though the tang records are really old, people still listen to them and appreciate them today because they're like a window into history. So that's why they're considered "great" - they give us a glimpse into a very important part of Chinese culture and history.