Place 2 pieces of fabric together with wrong sides facing each other. Sew an overhand stitch just under 1/4".
When overhand stitch is completed, turn the fabric so that the 2 pieces are now facing with right sides together. You then do a running stitch so that your overhand stitch is encased between the right sides of the fabric.
The final step is to open up the fabric with the back side facing you and hem stitch that 1/4" encased seam down. The right side of the fabric will just show the tiny hem stitches. The back side of the fabric will show the running stitches.
Ever since 2007, I have become fascinated with this ancient type of Korean patchwork and have done lots of research to try and learn how it is done. There aren't any books in the USA (that I could find) that actually describe the procedure. I have gotten hints from many different sources and have done lots of experimenting. I think I finally have gotten it right.
The word pojagi refers to square hemmed cloth of various sizes, colors, and designs, which Koreans used to wrap, store, or carry things. Pojagi was not only for practical and versatile items in the daily lives of Koreans, but was also very artistic. Most of the pieces are done with sheer silks, linens, and cottons that are transparent and, therefore, the seams becme part of the design when held up to the light. If you are interested in reading more about this, research the words pojagi, bojagi, chokakpo and gekki stitching.
I am posting some pictures with explanations of how this is done. Feel free to e-mail me if you want to try this and my explanation is not clear.