Turning an Oval into a Circle

Exploring 20-meter circles from the judge's perspective.
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Credit: Margaret Freeman Note the scale above M on this clipboard, showing 6 meters from the corner to M and 12 meters from M to R. The cloisonné ”horse” is crossing the center line 2 meters past the line between R and P.

Credit: Margaret Freeman Note the scale above M on this clipboard, showing 6 meters from the corner to M and 12 meters from M to R. The cloisonné ”horse” is crossing the center line 2 meters past the line between R and P.

How big is a 20-meter circle? Uh, is this like that “Jeopardy” Stupid Answers category? It’s 20 meters, isn’t it? How about 66 feet?

A scribe asked me recently how I can tell if a circle is actually 20 meters and truly round, when it’s at the far end of the ring or even in the middle. Of course, when I’m sitting at C, it’s not as easy to see the geometry of a circle as it would be if I was sitting on the side at B or E. Therefore, I determine the size of a 20-meter circle by looking for points of reference, just as I would if I was riding a test myself.

This is easier to figure out with a short arena, 20 x 40 meters, because it’s the length of two 20-meter circles. Therefore, a circle that starts at A or C passes right through X. A standard arena is, of course, the length of three 20-meter circles.

The big mistake people often make when trying to ride 20-meter circles is to aim for the line between R/P or S/V, crossing the center line at “I” or “L.” That turns a “circle” that starts at A or C into an oval because they are crossing the center line 2 meters short. They do something similar when riding a 20-meter circle that starts at B or E, aiming for that line between R/P or S/V, but that distorts the circle even more, turning it into a huge egg.

The key is to understand the distances between the letters. From the actual corner to a “corner letter” is a distance of 6 meters, while the distance between the “funny” letters of RSVP and the “regular” letters of MFKH or EB is 12 meters. Therefore, a circle that starts at A and crosses the center line at L is only a squished 18 meters, and a circle that starts at E or B and crosses the center line at L or I is a bloated 24 meters.

So, how big is a 20-meter circle if you’re riding a test? Visualize the line between R/P and S/V as a point of reference, but ooze past that line if the circle starts at A or C. If the circle starts at B or E, then cut inside that line.

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