Don't worry, I know there's a warping error. I was watching a youtube video about warping a loom by yourself, and messed up. I'm glad that the warps will be covered in this piece.
So what is sakiori? Here's a good description from Sri. Sakiori weaving uses a rag weft against a warp of either bast fiber or cotton. The weft material is often made from shredded kimono or other recycled garments which can be of cotton, silk or other material. Sakiori clothing was first woven by Japanese peasants around 1750 for its warmth and durability as newly minted cotton cloth at that time was too rare and expensive for a farmer or fisherman. The home manufacture and use of sakiori clothing and hearth covers in rural areas of Japan disappeared anywhere from 50-100 years ago, although a few individuals and some historical preservation societies still weave this cloth today.
For this sash, the warp threads are cotton, and the strips are a mix of recycled cotton and silk.
Here are a few examples:
This book is a very good resource.