I got 97% for my textiles exam at college - from an extremely well known professor who never gave As?

Here's a link telling you what a chambray weave is. It's the name for a plain weave made of cotton - which is what today's denim is made of.

https://thefabricofourlives.com/cotton-fabrics/chambray

I don't think I've seen a pair of denims in a twill weave for 20 years. Perhaps, at the very high end, but virtually all denim today has elastine in it, and it is a plain weave.

And, yes, I do have a degree in this stuff.

Perhaps it's different in Japan, but none of the countries I have lived in - US, UK, Africa, EU,