Transparent Kimono with Lines in It - Real or Fake?

My economic situation in college encouraged a lot of thrifting, which is where I picked up my first few kimono. One of them, I decided, was a fake or underwear because it had open lines running through the weave of the fabric that made it half-transparent.

Years later, after throwing it away (doh!), I learned that's just "summer weight" weave and is completely kimono-legitimate. There are few specific kinds of summer weight weaves, one of the most common being "ro" weave, where you can see through lines to the layer underneath.

Here are a few examples of summer-weight pieces:

"Ro" men's formal haori jacket detail (family crest)

Look carefully at the first maiko's collar and the sleeve of the second one to see the telltale lines in their kimono. Bottom two photos by Onihide and used with permission.