Fang Yun listened attentively to their explanations, combining them with the various books on the qin he had read before, he began to sort out the similarities and differences between the qin paths of the two worlds in his mind.

"From an appraisal perspective, both worlds place equal importance on the structure, material, tone, and age of the qin. The factors of the qin maker, also known as the qin craftsman, also need to be considered. However, the qin craftsmen of the Holy Origin Mainland also need to appraise an additional item, the 'weight number'. Besides, the Holy Origin Mainland's research on materials is more detailed, because the Treasures of Literature have higher requirements for materials. But by overemphasizing materials and weight numbers, less research is done on the age. On the other hand, the ancient Huaxia nation of the other world, due to many people collecting ancient qins, has deeper research on the age than the Holy Origin Mainland of this era."

Fang Yun continued to sort out his thoughts and found that the Holy Origin Mainland currently does not have a complete "theory of age determination by crack patterns". The so-called crack patterns are traces left on various parts of the qin body due to the interaction of time, environment, and playing. There are snake belly cracks, flowing water cracks, fish scale cracks, cow hair cracks, etc. This is the most important method for Song Dynasty qin craftsmen to appraise the age of ancient qins.

However, Fang Yun still found some books on the Holy Origin Mainland mentioning "crack patterns", but none of them systematically sorted out these crack patterns. The "theory of age determination by crack patterns" still does not exist.