Solo instruments are considered to be the most serious form. The sound of this type of music is almost similar to the sound of poetry being recited. There are relatively few compositions of this type. Many of the ones that do exist, however, are very old and added to slowly over the years. Often recordings and performances of this type vary.
Anthologies are the best way to sample the Chinese classical music.
A seven stringed zither called the qin is considered to be the most scholarly instrument. There are playable qins from as long ago as the Tang dynasty. The zheng is a movable bridge zither. It is considered China's most dynamic instrument. It's technique is very complex and much has been written for the instrument in modern times.