The octagon and other tips to improve your 20-meter circle
The ubiquitous 20-meter circle is simple, but not easy to execute correctly. I have always been a strong believer that riding correct figures goes a long way, in and of itself, in training every horse. Anne Gribbons recounts in her book Collective Remarks a story of Herbert Rehbein hopping on her horse and riding “exactly one 20-meter circle in canter,” which proved to permanently correct a straightness issue in the Grand Prix horse’s one-tempis.
While Mr. Rehbein’s mastery is legendary, I would like to offer a few tips to help you ride more correct, and therefore more effective, circles. Firstly, it is important to understand the dimensions of the dressage arena, the placement of the letters, and the distance between them (see Figure 1). If you do not have a regulation-size arena, you would do well to measure and mark these distances with cones, ground poles, or a mark on the wall or fence.

The purpose of the circle is to clarify the rider’s boundaries and bending aids, while working towards symmetry in both directions. Some common mistakes include over-positioning the horse’s neck to the inside and allowing the shoulders to pop out, letting the horse get stuck to the wall and go too deep into the corners, or letting the circle collapse on one side and bulge out on the other. I have found that riders are able to bend their horses much more correctly once they tackle these basic steering issues.
When introducing circles, I always recommend beginning with a diamond, with four straight lines and four square turns at each point of the diamond. At first, this may seem awkward and crude, but it helps clarify correct boundaries. It is important for the rider to look directly between the horse’s ears and to keep the horse’s withers in front of her sternum. As riders gain control of the horse’s shoulders in the turns, the leg aids can be applied to control the barrel and hind legs to add bend. The rider will need to be reminded to weight the inside seat bone slightly to support the lateral balance.
It is much more beneficial to practice the circle in the middle of the arena (between B and E), as neither horse nor rider can use the walls as a crutch for turning, as they might do when practicing at A or C. If one does practice at A or C, it is important to only touch the wall or fence for one step at each of the diamond’s four points and to avoid the corners altogether.
Some folks struggle with looking down, which can wreak havoc on proper geometry and bend. If you lift and soften your gaze, you can use your peripheral vision to take in the whole arena and assess exactly where all parts of the horse are, in the space of the arena. It is helpful to contemplate what you might see behind you, if you had eyes in the back of your head. Your success in good geometry will be much improved with this important component of good riding.
From the diamond, you can then refine the turning aids by thinking about riding an octagon. Instead of a square turn on the diamond’s four corners, the rider will make a less severe turn, followed by a couple of steps straight ahead, followed by another small turn, keeping in mind the four points that clarify where your circle belongs in the space of the arena (see Figure 2).

Once the basic steering is in place, magically some of the components of bend have started to be installed already. The rider will have learned to limit neck bend with the outside rein and utilize his inside and outside legs to ensure the horse’s body follows the front end. So now, we refine and clarify that the rider’s inside leg should push the barrel outwards and ask for engagement of the inside hind leg. The outside rein continues to ensure that the shoulders stay on the line, while the outside leg ensures that the haunches don’t swing out. And the inside wrist and fingers ask for inside flexion from the poll.
Frequent changes of direction are also important! Repeating the same circle fifteen times in a row tends to be counterproductive. If one direction of the circle feels especially difficult, the other direction will often refresh and inspire improvement on the more challenging side. Use the Yin and Yang sign to change through the middle of the circle (see Figure 3). This may seem incredibly difficult and may be performed at the walk first, but it is a valuable exercise in steering the shoulders!

Perhaps just as important as mastering the circle line is leaving and returning to the circle. As soon as a rider can perform the circle as described above, moving on to a pattern similar to a Training Level test is important. For example, ride the corner before A, ride one circle at A (avoiding the corners), then ride the second corner after A. You may wish to continue around the arena, adding a circle each at B, C, and E. Proper corners for the lower levels are ¼ of a 10-meter circle. After riding a single circle at each letter, change your direction across the diagonal and repeat the circle at each letter in the other direction. Riding the whole arena refreshes the rider’s perspective, prevents drilling, and helps both horse and rider gain agility in moving from one movement to another.
The 20-meter circle sets the stage for three loop serpentines. At more advanced stages of training, lateral exercises such as shoulders-in, haunches-in, and renvers, as well as medium gaits and transitions between the gaits, can be ridden on the circle. Even as simple an exercise as adding a 20-meter circle between other exercises can help to rebalance and supple the advanced horse.
Jennifer Grant is a USDF Certified Instructor, USDF Bronze and Silver Medalist, and L Graduate with Distinction