A sash is of a cloth belt used to hold a robe together, and usually tied about the waist. The Japanese equivalent of a sash, called an obi, serves to hold a kimono together. Decorative sashes may pass from the shoulder to the hip rather than around the waist. Sashes traditionally form part of formal military uniform and the royal attire.
The meaning "strip of cloth worn about the waist or over the shoulder" was first recorded in 1681. 
- "Online Etymology Dictionary". etymonline.com. http://www.etymonline.com/index.php?search=sash&searchmode=none. Retrieved 6 May 2010.