The sageo is the braided cord threaded through the kurigata - the knob on the saya - and in traditional koshirae it served a functional role securing the scabbard to the obi. Over time it became one of the most expressive aesthetic elements of a katana's full mounting. White specifically carries associations with purity and formal intention in Japanese aesthetics. On a finished piece, a white sageo creates a sharp visual contrast against both dark and light saya finishes, drawing the eye along the scabbard in a way that colored cords rarely achieve. Collectors who understand koshirae composition often evaluate the sageo alongside the ito wrapping and tsuba design as part of a unified aesthetic system rather than treating it as an afterthought.