The sageo is a cord or braid that is attached to the saya, the scabbard of a katana. It serves several practical and decorative purposes:

1. Securing the Katana: The primary function of the sageo is to secure the katana in the saya. It is tied around the kurigata, a small knob or loop attached to the saya, and then wrapped around the saya in a specific manner. The sageo helps to hold the katana in place, preventing it from accidentally slipping out of the scabbard.
2. Grip Assistance: When drawing the katana, the sageo can provide additional grip and control. By looping the sageo around the hand or fingers, it offers a firmer grasp on the saya during the draw, making it easier to smoothly and efficiently unsheathe the blade.
3. Decoration and Aesthetics: The sageo also contributes to the overall aesthetic appearance of the katana. It can be made from various materials, such as silk, cotton, or synthetic fibers, and comes in different colors and patterns. The choice of sageo can reflect personal preferences, individual style, or traditional customs associated with a particular school or style of swordsmanship.
4. Symbolic Significance: In some Japanese martial arts traditions, the sageo may have symbolic significance. It can represent the practitioner's dedication, loyalty, or status within a specific school or organization.

It's important to note that the wrapping and tying of the sageo can vary depending on the specific style or school of swordsmanship. There are different methods and patterns for securing the sageo to the saya, and the tying technique can hold cultural and stylistic significance within different swordsmanship traditions.