What is kugurizashi? Kuguri literally means 'go through', and it is a kind of hitomezashi (one stitch sashiko) where you can create beautiful designs by threading or weaving thread, often in a different colour, through simple rows of running stitch. I recommend turning your needle around when you do the threaded part, so you don't accidentally pierce your previous stitches. The running stitches are printed on the panel, and the instruction leaflets show you how to thread. Fun and quick to make!
This video from manufacturer Olympus Thread Mfg. Co. shows how to stitch two kugurizashi patterns, and this one shows two more.
They are printed on sarashi, a soft, slightly absorbent traditional Japanese cotton, and may be stitched through two layers (the backing is attached) or through just one layer. Marks wash out later. Each sampler comes with easy to follow instruction diagrams and instructions in Japanese (which may be 'read' in your language by using the Google Translate app).