She uses it to make some really neat table runners. I really like the patterns.
The greatest thing about Sashiko is going to the local yarn store together to pick out various perle cottons! When I saw what my mom was using, I said, "This is just perle cotton! Look at the huge cones you could get for a much better price!" Now we both have an excuse to stop in occasionally to the yarn shop!
She's also discovered the thick and thin weaving yarn! It gives it a whole new look!
My mom is really into quilts and Japanese fabrics so she turned some of her Sashiko projects into really neat looking quilts. They are very eye-catching!
I asked my mom to write up a little bit of sashiko history. Here is what she said:
Sashiko evolved as a rural domestic craft in Japan during the Edo era (1615-1868). Cloth was a scarce resource and something to be used and used over again in various ways until it fell apart into nothing. Farmer’s wives would sit by candlelight in their thatched-roof farmhouses, mending clothing by using a simple running stitch to mend and strengthen. Often another layer of fabric would be added and the stitching would hold it into place. At first this was a very utilitarian way of mending fabric and the stitches were simple and rather large. As fabric became more available to the people, the stitches evolved into more decorative ones and the craft also moved from Northern Japan to other areas of the country. Kimonos and other clothing items were remade into work wear and sleep wear, then finally into bags and aprons until finally the clothing became diapers, rugs, and cleaning cloths. 
Sashiko literally means “little stabs” and the stitches have been said to appear like grains of rice on the fabric. Historically, the stitching was always done on an indigo fabric ground with white thread. As the craft developed, the designs became much more complicated and mainly were nature-based with patterns such as hemp leaves (Asanoha), bamboo (Kagome), tortoise shell (Kikko) and ocean waves (Seigaiha).
Stitching sashiko is an easy and relaxing hobby, often zen-like because it is so relaxing and beautiful. The supplies are simple and readily available. Traditionally indigo fabric and sashiko threads are used, both of which are imported from Japan and easily found on the internet. I have found the best place to get supplies is www.shiboridragon.com with the website full of many wonderful items and everything you need to get started. Recently I have begun to hand dye my own indigo fabrics, which gives wonderful shades of rich blues that are not commercially available. All the information and supplies to do this are available at www.dharmatradingcompany.com and while it can be a messy endeavor, it is well worth it for the wonderful blue fabric I have been able to get for a fraction of the price of purchasing someone else’s hand dyed fabrics. If a person just wants to dabble around a bit in sashiko, it is quite adequate to purchase perle cotton, either 5/2 or 10/2. If using 10/2, it is always used doubled, which is the traditional way to use sashiko threads. Kaufman Kona cottons are quite nice to stitch on and widely available at stores such as JoAnns. Stitching is done without a hoop and with a needle that is rather long and sharp. Many books are available online and at local libraries with the “bible” of sashiko being “The Ultimate Sashiko Sourcebook” by Susan Briscoe.
Keep on Sashiko-ing!