sashiko

thumb|Detail of a mid-19th-century kimono decorated using , with white [[cotton threads on an indigo-dyed plain weave background (Metropolitan Museum of Art)]] thumb|upright=2|Child's sleeping mat (), late 1800s. The stitches are decorative, but also functional; they hold the pieced cotton rags together

is a type of traditional Japanese embroidery or stitching used for the decorative and/or functional reinforcement of cloth and clothing. Owing to the relatively cheap nature of white cotton thread and the abundant nature of cheap, indigo-dyed blue cloth in historical Japan, has a distinctive appearance of white-on-blue embroidery, though some decorative pieces may also use red thread.