About Olympus Fabrics:
The Olympus Thread Mfg. Co., Ltd. of Nagoya, Japan, has been A Threaded Needle's main Sashiko supplier since 2005. I choose them for their knowledge and manufacturing standards, first for sashiko products, and recently more and more for their interesting and exceptional quality fabrics.
It isn't always necessary. It depends on the quality of the fabric and the purpose of your project....