I have just begun teaching myself how to “read” thread counts, and I have encountered a question that I hope someone here will be able to answer.

From what I have read online, the overwhelming majority of tartans are designed to be symmetrical. To my understanding, this means that a thread count of (very much simplified) “A-B-C-D-E-F” would then be reversed “E-D-C-B-A” and then repeated “B-C-D-E-F” and so on and so forth.

The rare tartans that are described as nonsymmetrical do not have the revered part; so that “A-B-C-D-E-F” would be followed immediately by “A-B-C-D-E-F”.

However, I have seen a fair number of tartans that are listed as nonsymmetrical with a thread count of “A-B-C-D-E-F-E-D-C-B”, which would be the exact same thing as a symmetrical thread count of “A-B-C-D-E-F”.

So my question is: What the heck am I missing here? Are there really two acceptable ways, symmetrical and nonsymmetrical, to describe the same tartan?

Also, while I have you here: Is there any convention about which stripe is considered “A” or is it completely the random choice of the tartan designer?