Delicate yuuzen-dyed haneri (decorative collar) by Uenaka Masashige.
Normally, this part of a haneri is left patternless. On their webshop, those products are nicknamed [chirari], a term meaning “a fleeting glimpse of something”, here hinting at the fact that in Japan the nape is seen as quite sensuous (like a décolleté in the West), so putting a pattern there draw the eyes.