Sashiko boro is the Japanese folk practice of mending worn indigo-dyed cotton and hemp with white running stitches, layering patch upon patch until a garment becomes a palimpsest of deep navy fragments. Born of pre-1900 rural thrift, it reads as a dark kon-iro field gridded with fine ecru stitching and broken by sun-faded lighter-blue patches.

This design system translates that worn cloth into an interface: deep indigo grounds, overlapping rectangular patches with visible seams, dense hand-stitch geometric grids, and the occasional madder-red mend. The surface is woven fabric, never paper.