"It's not just about distance," Yasui Makoto said, recalling the training schedule as he walked to the wall and opened his travel bag. "The real purpose of this special training isn't simply to run farther."
He pulled out the equipment and continued, "Instead, we're using this to train vertical displacement, body coordination, and control of your center of gravity and power."
"So for the upcoming sessions, how far you can run on the wall is secondary. The key is whether you can meet the requirements."
Kitasan Black leaned in obediently, watching with curiosity as he laid everything out.
"Put these on first."
"What is this...?" she asked.
"A helmet, buffer suit, knee pads, elbow pads, and wrist guards," Yasui Makoto explained casually while fitting a specially designed helmet over her ears. "I told you before—real Extreme Stunts carry risks, whether in training or an actual performance."
He helped her into the rest of the gear, his tone steady. "Take vertical wall running, for example. In a real show you'd have to perform specific movements while running, including precise starts and landings. Even though we're not practicing those complex moves yet, the height and arc of your runs will be far more demanding than before."
"When you first start, you're very likely to fall. That's why the protective equipment is essential."
Once she was fully geared up, he reached into the bag again and pulled out a thick stack of plastic sheeting and a portable air blower. Under Kitasan Black's watchful eyes, he spread the sheeting along the base of the wall and connected it to the blower. A low whoosh filled the air as the material inflated into a wide safety mat—over a meter across and six or seven meters long.
Kitasan Black touched the strap under her chin, then glanced down at the padded suit hugging her waist and the thick mat at her feet. When Yasui Makoto had first mentioned the training would involve risks, she hadn't thought much of it. Now, seeing the full setup, the reality of what lay ahead sank in. A quiet nervousness stirred in her chest.
Yasui Makoto picked up a piece of chalk and began marking the wall at different heights.
"Generally speaking, the Japanese Derby tests a Uma Musume's overall explosive power and endurance," he said, tilting his head toward her. "That demand comes from the track's multi-stage undulations."
"There's a long downhill right after the gate with a 1.9-meter drop. After that slope levels out for a while, there's another continuous downhill of about half a meter. Before the third turn, the track climbs 1.5 meters, then drops again through the middle of the turn—steeper this time. Before the final turn it rises once more, this time with a 2.4-meter height difference over a long stretch, leading into the final straight."
"Compared to other races, the slopes of the Japanese Derby are relatively gentle. But the total accumulated elevation change of over five meters still drains a lot of stamina. Because the changes come in segments, if you don't adjust your rhythm in time, it's easy to fall out of sync—and one small mistake can leave you exhausted in the later stages."
He looked at her. "Now you understand why I said your earlier practice wasn't enough."
Several height marks now stood out clearly on the wall. Kitasan Black stared at them, her nervousness sharpening. In her previous wall-running drills the path had always been a smooth, continuous arc. These marks, however, showed fragmented rises and drops that mirrored the Derby's layout. There was no way to treat it like a simple straight run.
She understood the difficulty now. On flat ground she could handle uphill or downhill sections without worrying about height. But isolating those vertical changes and forcing her body to manage them on the wall made every mistake potentially costly. Without the gear and the mat below, a fall would mean real injury.
Still, after the initial wave of nerves, another thought surfaced. When she had first started learning Extreme Stunts, Yasui Makoto told her that if she could treat a perfectly vertical surface like flat ground, then any slope on a real track would feel manageable by comparison. This training was built on that same principle. The Derby's undulations were complex, but if she could adapt to these controlled drops on the wall, the actual racecourse would feel far more manageable.
"...Let's begin, Trainer."
She flexed her wrists inside the guards and rolled her shoulders, eyes locked on Yasui Makoto.
"I told you—I'm completely ready."
Yasui Makoto had been about to offer more instructions, but her determined words made him smile.
"All right. We'll start with the 1.9-meter mark. The goal is simple: reach that height on the wall as quickly as possible and hold it for as long as you can."
He stepped back, stopwatch in hand.
Kitasan Black settled into her starting stance. Her tail flicked upward, then settled—the small habit she kept before every special training session and every gate entry. This time her opponent wasn't another Uma Musume. It was the wall itself.
"Ready... start."
At his signal she exploded forward. The moment her foot struck the wall she gritted her teeth. Adding a strict height requirement had made the already familiar drill dramatically harder.
Her first attempt fell short. Her foot landed just below the chalk line. A flicker of panic hit her; she tried to push higher. But vertical force and controlled perpendicular force were entirely different. The moment her toes twisted against the surface, the muscles along her thigh cramped. Control slipped.
She twisted at the waist, swung her arms, and kicked out with her free leg, desperately searching for a new foothold. The wall suddenly felt impossibly slick. She managed to shift her center of gravity for half a second—then the world spun. The shoulder straps of the buffer suit yanked tight, and her back slammed into the cushioned mat.
For a moment she lay there, blinking up at the ceiling.
...That was a failure?
A light tapping sound reached her through the helmet. Yasui Makoto's face appeared above her, upside down, wearing a faintly mischievous grin.
"How was that? Didn't I say you hadn't practiced enough yet?"
He tapped the top of her helmet once, then his expression turned serious.
"Consider this your first real attempt at the new training. We'll start over from here."
"Remember what I told you—Extreme Stunts aren't about raw power. They're about using every part of your body freely and intelligently."
"This time, adjust your foot placement angle—tuck it in a little more. And apply force with your ankle a fraction earlier when you drive up the wall."