obiage
Obiage (帯揚げ, "obi bustle") is a scarf-like piece of cloth and it is a beautiful piece of fabric that serves the purpose of covering the makura (pillow) and usually helping to secure the bow of the obi (keeps the upper part of the obi knot in place). These days it is customary for an unmarried, young woman to let her obiage show from underneath the obi in the front. A married woman will tuck it deeper in and only allow it to peek. Obiage can be thought of as an undergarment for kimono, so letting it show is a little provocative.