A regulation World Taekwondo Federation sparring ring is an octagon that's 8 meters across. Laying-out an octogonal ring onto square mats can be difficult. This wiki page will teach you how to make an octagonal template using rope.
A sparring ring that is 8 meters across should have sides that are 3.314 meters long. If you try to lay-out an octagon using square mats, the corners will be too short, and the edges will be too long. A more accurate solution is to use rope to create a "template" for a regulation 8 meter ring.
For a regulation 8 meter ring, the diagonals that run across the center of the ring should be 8.659 meters long. You will need four ropes that are 8.659 meters long to form the diagonals of the template.
The perimeter of the ring is 26.510 meters long. To build the template, measure a perimeter rope that is 26.510 meters long, with markings along the perimeter at every 3.314 meters. That will give you a perimeter with 8 edges.
Connect the opposite corners of the perimeter with with the center ropes. Now, when you pull all the ropes taught, you'll form a perfect octagon.
- You'll need a single rope that's at least 26.510 meters long for the perimeter. In the U.S., that means buying a 100 foot rope.
- Each rope should be marked with the correct dimensions (for example, using a Sharpie) but you should leave a few extra inches on either end of each rope. You'll want those extra inches for tying or fastening the corners.
In the example shown here, polycord rope was used, and zip-ties were used to fasten the corners. In the photograph below, notice that we were careful to ensure that the black Sharpie marks line-up where the center rope meets the perimeter rope.
For smaller venues, you can also make 7 meter or 6 meter rings.