"Perhaps the most important method for preserving eggs is the one that produces pidan, or eggs coated on the outside. Depending
on preference, methods may be modified to produce songhuadan (pine floral eggs) or caidan (colourful eggs). The earliest known
description of an egg preservation method is that of Wang Zizhen during the Ming Dynasty about 500 years ago. Blunt and Wang
described an essentially similar method in 1918:"