Asahi came to a halt in the corridor of the Scripture Repository.
"Koyoi. Fix your stance."
"Huh?"
Koyoi looked down at his feet. He was standing on the stone paving in a perfectly ordinary manner.
"What’s wrong with it?"
"Your weight is too far forward. One shove and you’re down."
Asahi demonstrated his own stance. His feet were shoulder-width apart, knees slightly bent, his center of gravity lowered. It was entirely different from the way Koyoi was standing.
"I’m not teaching you the sword—we don't have time for that. But you can at least learn how to stand if you want to stay alive."
Koyoi tried to mimic Asahi’s posture. As he bent his knees, he felt the strain in his thighs.
"This is hard..."
"You’ll get used to it. Next, look at the shadows."
Asahi pointed to the wall of the corridor. The light from the lanterns cast three shadows against the surface.
"When an enemy draws near, their shadow moves before they do. If you know where the light is and where you’re standing, you can read what’s behind you just by watching how the shadows shift."
"By the shadows?"
"If you can see it, so can the enemy. Learn to catch what your eyes miss."
Kuon was sitting further down the passage, leaning against the wall with a ledger spread open. He scribbled occasionally with a pencil while listening to their conversation.
Asahi stepped in front of Koyoi.
"Close your eyes."
"...They're closed."
"What do you hear?"
Koyoi focused his senses. The interior of the Repository was quiet, but it wasn't absolute silence.
"...The walls are creaking. A low sound. And the sound of Kuon’s pencil. And then—"
Koyoi tilted his head.
"—The wind. There’s a breeze coming from somewhere. From the right."
"That’s the one," Asahi said. "Airflow tells you the shape of a space. A breeze means there’s a passage in 그 direction. Where the air is still, it’s either a dead end or something is blocking the way."
Koyoi opened his eyes. Sure enough, there was a narrow gap in the right-hand wall. A faint draft was trickling through it.
"In the Repository, the records can stir on their own."
Asahi’s voice dropped an octave.
"Sometimes paper falling from the shelves will come flying at you like a blade. You saw it in the Archive Room, didn't you? When that paper disintegrates, the dust gets in your eyes. That alone is enough to leave you helpless."
Koyoi recalled the scene in the Archive Room—the paper that had crumbled at the mere touch of a finger. If that powder got into his eyes...
"So, read the shifts in the air. The air shifts before the paper does."
Asahi placed a hand on Koyoi’s shoulder.
"Don't move your feet. From where you're standing, measure the distance to the walls with your hands."
Koyoi reached out. To the right wall, one arm's length. To the left, it was a bit further.
"If you know the distance to the walls, you can move even in total darkness. Kuon is a different story with that prosthetic eye of his, but in the dark, you and I are the same."
Kuon looked up.
"The eye is not omnipotent. The azure light illuminates the records, but it is of no use in places where no records exist. The lowest levels of the Deep Stratum were almost entirely dark."
Asahi nodded.
"That’s why the three of us compensate for each other. Kuon reads the records. I deal with physical threats. And Koyoi—"
Asahi looked him in the eye.
"You read the air. Catch the shifts long before the Shizuku reacts. That is your role."
Koyoi touched the pouch at his waist. The Shizuku was quiet.
"Read the air..."
"Don't overthink it. It's the same thing you just did. Your stance, the shadows, the wind. Learn it all with your body."
Asahi took his hand off Koyoi’s shoulder and leaned back against the wall.
"That's all I can teach you for now. You’ll have to learn the rest in the field."
"...Thank you, Asahi."
"Just stay alive and keep moving. That’s thanks enough."
Kuon added another line to his ledger.
Koyoi couldn't see what he had written, but as he set his pencil down, the corners of Kuon’s mouth turned up in the slightest of smiles.
The lanterns in the corridor flickered. For a fleeting moment, the three shadows on the wall overlapped, before pulling apart once more.