[Different lots of yarn] Even yarns of the same color may not be used.

In the dyeing story, we talked about blending five or six colors of cashmere to make wadding, and spinning this blended wadding. Since dyeing and spinning are a single set, the yarn always has a spinning lot number on it.
In making cashmere knitwear, we always check the spinning lot number, and if the lot numbers are not matched, we will be in trouble.
The most troublesome problem with different lots is the difference in color. Even the same color is slightly different between different lots. Even if you compare the yarns (cones), you cannot tell the difference at all, and even if you are careless and start knitting with yarns from a different lot because they are the same color, the human eye can tell the subtle difference. The human eye is amazing.