Why are wild wenwan walnuts often irregular?

This is an English reading overview of the Chinese article, rather than a complete translation. The Chinese source has been updated since this overview was prepared; consult the original for the latest details.

The central idea

Trees, seasons and growing conditions vary, so shape, ridges and pairing may be less uniform. Natural variation can be acceptable, while cracks and structural damage still need to be excluded. Irregularity alone does not establish quality. The separate pairing guide explains why closely matched wild pairs can be difficult to find.