X doesn’t always mark the spot for many riders. Yes, it’s on the centerline directly between B and E, but often riders drift closer to the quarter lines, or halt too early or late.
If you’re straight on the centerline but halt early or late, the judge at C may not be able to tell that you missed X. However, it’s painfully clear to a judge at the side, so if you plan to show in competitions with more than one judge, like most championships, you want to gain confidence about how to land right on top of X.
I frequently see riders looking side-to-side toward B and E as they prepare to halt. It usually doesn’t seem to do them much good, since the side-to-side motion becomes a distraction. When you enter at A, you want to lock eyes with the judge as you go down the centerline, as if you daring her to give you anything less than an 8 there.
However, there is a foolproof way to find X, and it’s really very simple. Keep your eyes on the judge after you enter at A, and when E and B disappear from your peripheral vision, then halt. You should be directly over X or very close to it. Interestingly, this seems to work equally well with any of the three gaits, whether in working or collected, perhaps because the different levels of balance correspond to the timing of sighting B/E out of the corners of your eyes.
If you want to practice this at home and don’t have a measured arena, you can do so by simply placing a couple markers, like buckets or soccer cones, to form a line approximating A and C. Then place two markers centered on that line across from each other, 66 feet apart, to approximate B and E. Ride toward the C marker, and when the B/E markers disappear from your peripheral vision, halt. Check to see whether you are directly between B/E or a bit early/late. Then ride the line again until the timing of your half halts put you right over X.