This is a fragment of an under-silk kimono. It was used for the sleeve part of an old silk kimono.
 
These silk parts are called Tsumugi silk length.  A "tsumugi kimono" refers to a type of kimono made from tsumugi silk, a textured and irregular silk fabric, giving the kimono a natural and slightly rustic appearance.
 
All hand sewing by hand Sashiko stitching.
 
Measures: 29cm×59cm (11in × 23in)