The 'sageo' is the cord used to secure the saya (scabbard) of the katana to the obi (belt) of the samurai. Whenever the sword was utilized for display, presentation, or otherwise removed and placed on a stand, it was a matter of etiquette to tie the sageo in a manner that prevented it from loosely hanging from the saya onto the floor or otherwise. As is common with Japan, this seemingly simple act developed into its own art form.
The word Samurai is taken from a phrase meaning "to serve". And thus a Samurai's life was one of service to his master, his community and the code of his order. At any given time the Samurai's nature was to be both infinitely compassionate and dangerous at all given times.