For some reason Chinese people (and their sphere of influence such as Japan) are obsessed by numbered lists, e.g. stuff like Four Beauties, Four Treasures of the Study and so on!
The concept does exist in the West (e.g. The Seven Wonders of the World), but clearly the Sinosphere is much more obsesse by it!
Figure 1. A modern rendition of the four beauties. Source. TODO we need a decent older one with CC BY-SA, and illustrating their attributes! Wikimedia failed me.
Figure 1. Source.
Video 1. Four Treasures of Chinese Study by a journey of culture (2022) Source. Over the top and likely without copyright.
Video 2. Four Treasures of the Study by Li's Ink World (2021) Source. A more realistic down to Earth one.