The joint training notice arrived the following morning, slipped under doors with the efficiency of a system that didn't ask whether the timing was convenient.
Kaito read it standing in the doorway of his room with his uniform half-buttoned. Mandatory paired practical exercise, Training Hall B, 8:00 AM. Partner assignments listed at the bottom in Ijichi's precise administrative handwriting.
His partner was Megumi Fushiguro.
He finished buttoning his uniform and thought about that for exactly as long as it deserved, which was not long, and then went to find breakfast.
Training Hall B was larger than the evaluation room and smaller than the courtyard, a rectangular space with reinforced walls that had been repaired recently enough that the newer sections of plating were still a slightly different shade than the original. The floor was scored from previous sessions — impact marks, burn traces, the shallow gouges left by techniques that had gone wider than intended.
Megumi was already there when Kaito arrived.
He stood near the center of the hall with his hands in his pockets and the expression of someone who had decided in advance how this session would go and was waiting for events to confirm or revise that assessment. He looked at Kaito when he entered and said nothing, which Kaito was beginning to understand was not rudeness but a specific form of efficiency — Megumi didn't spend words on things that didn't require them.
The instructor was a woman Kaito hadn't seen before, compact and unhurried, with a Grade One designation on her jacket and the particular stillness of someone who had been in enough situations that ordinary ones no longer registered as stimulating.
"Paired application exercise," she said, without preamble. "The objective is coordinated technique deployment against a mobile cursed construct. The construct will adapt to your output patterns after the first exchange. You'll need to adjust." She looked at them both with the level attention of someone who had read their files and formed no strong opinions yet. "You have ten minutes to discuss approach before we begin."
She stepped to the side of the hall and became very still.
Kaito looked at Megumi.
Megumi looked at Kaito.
"Your technique fixes spatial positions," Megumi said.
"In the right circumstances."
"What are the wrong circumstances."
Kaito considered the question. It was the right question — not what can you do but where does it fail. He hadn't expected Megumi to open there, but he should have. Megumi's approach to everything, as far as Kaito could determine, was structural. He wanted the load-bearing walls first.
"High movement rate," Kaito said. "If the target is repositioning faster than I can recalibrate, the anchor loses validity before the team can act on it. And the technique requires a clear read on the spatial structure. If the target's pattern is irregular rather than layered, I don't have a clean geometry to fix."
Megumi absorbed this without visible reaction. "My shikigami need a stable target for accurate engagement. Fast repositioning is also the primary failure condition for Divine Dogs." He paused. "We have the same weakness."
"Which means we need a different entry condition."
"Yes." Megumi looked at the center of the hall where the construct would appear. "I force the initial engagement. The construct focuses on Divine Dogs — they're high-energy, high-movement, the natural priority target. While its attention is distributed, you read the structure."
"And when I have it—"
"Call it. I pull the dogs back and hit the fixed point."
It was clean. Simpler than Kaito had expected, which meant either Megumi was naturally economical or he had thought about this before the session. Probably both.
"The construct adapts after the first exchange," Kaito said.
"Then we don't give it a first exchange." Megumi's expression shifted slightly — not animation exactly, but the faint sharpening that happened when a problem resolved into something tractable. "We make the first exchange the finishing exchange."
Kaito looked at him for a moment.
There was something in Megumi's approach to combat that reminded him of the way his mother had described spatial containment in her debrief — the emphasis on reading the environment before committing to action, the preference for a single precise intervention over sustained engagement. It wasn't the same logic, but it came from the same instinct.
He didn't say any of that.
"All right," he said.
The instructor, from the side of the hall, said, "Time."
The construct appeared at the center of the hall in a compression of cursed energy that lasted less than a second — and then it was present, occupying space, a mass of concentrated malevolence with no fixed form and a movement pattern that changed direction without the mechanical pause that living things required.
Megumi's hands moved.
Divine Dogs manifested in the peripheral space of the hall, flanking the construct at angles that forced it to distribute its attention. They moved fast — faster than Kaito had expected, covering ground with the specific urgency of something that understood its role was to demand response rather than to land hits.
The construct tracked them.
Kaito read it.
The spatial pattern was there — not layered the way the school spirit had been, but structured, a central density with radiating extensions that reoriented toward the highest-movement target in the space. Predictable reorientation logic. The extensions were the reactive component; the central density was fixed.
"Center mass," he said. "Two meters up. The extensions are decoys."
Megumi pulled the dogs left simultaneously.
The construct's extensions followed.
Kaito's cursed energy left his palm as a flat crimson plane — not wide, targeted, fixed across the construct's central density with the precise dimensions of the structure he'd read. It held.
Megumi hit it.
One shikigami, one engagement, central mass. The construct destabilized from the inside — its extensions losing coherence as the core structure fractured, the whole thing dissolving in the specific way of cursed constructs when the organizing intelligence fails.
Four seconds from manifestation to dissolution.
The hall was quiet.
The instructor looked at her notes. She wrote something without commenting on it, which was either good or neutral and probably not bad.
"Second construct," she said.
The second construct was faster.
It appeared in the same location but moved immediately upon manifestation, crossing half the hall in the time it took Megumi's dogs to orient. The spatial pattern was irregular — not layered, not structured, a chaotic distribution of density that shifted each time Kaito tried to read it.
He had told Megumi this was his failure condition.
He tracked it for three seconds and found nothing clean to fix.
The dogs engaged anyway, buying time, driving the construct into the corner of the hall where movement options narrowed. Megumi was watching Kaito with the peripheral attention of someone managing two problems at once.
Kaito pushed harder.
His cursed energy came out not as a targeted plane but as a spread — wider deployment, lower precision, covering more of the construct's movement field in the hope that the irregular pattern would resolve into something readable under pressure.
It was the wrong decision.
The spread destabilized before it found a geometry, the pigment dispersing in the air without fixing anything, and the construct moved through it with the indifference of something that didn't recognize the attempt as a threat.
And then the domain moved.
Not fully — not the way it had in the corridor when the first-year training spirit escalated past Grade Two. More like a breath, a single expansion, the boundaries of the incomplete space pressing outward from Kaito's position before he caught it and held it back.
But it was visible.
The air in a two-meter radius around him changed quality for approximately one second — the light, the spatial texture, the specific sense of a boundary being asserted. The instructor's head came up from her notes. Megumi's eyes moved to him with the sharp attention of someone recalibrating in real time.
Kaito closed it.
The construct, briefly disoriented by the spatial shift, slowed its movement pattern for half a second.
Megumi didn't need more than that.
The dogs hit the construct from both sides in the moment of hesitation. Not a clean fix, not the precise single-engagement approach they'd used on the first construct, but effective — the accumulated impact fracturing the density enough that the construct destabilized.
The hall was quiet again.
Kaito stood with his cursed energy pulled back hard against his sternum, doing the internal equivalent of holding a door closed against something that wanted to push through it.
Megumi walked over.
He stopped two meters away, which was not the distance of someone who was afraid but the distance of someone who was thinking, and looked at Kaito with the dark, assessing expression that meant he was running a calculation he hadn't finished yet.
"That wasn't the spread technique," Megumi said.
"No."
"What was it."
"A containment reflex." Kaito kept his voice even. "My technique defaults toward enclosure under pressure. I can control it. I did control it."
"For one second."
"Yes."
Megumi looked at him for a long moment. The instructor was writing again at the side of the hall, and Kaito was acutely aware that whatever she was writing was going upward in the reporting chain and would arrive on someone's desk before the afternoon.
"Does it always do that," Megumi said. "Under pressure."
"I'm learning the conditions."
"That's not an answer."
"It's the accurate answer." Kaito met his eyes steadily. "I could give you a cleaner one that's less true."
Something moved in Megumi's expression — not warmth, nothing that comfortable, but the specific shift of someone who has pushed on a wall and found that it pushes back with consistent resistance rather than unpredictable collapse. It was, Kaito thought, the closest thing to respect that Megumi's face currently had available.
"The first construct," Megumi said. "Four seconds. That was clean."
"The geometry was readable."
"Most geometries are readable if you know what you're looking for." He paused. "You read it faster than I expected."
"Your setup gave me time."
"I gave you three seconds."
"That was enough."
Megumi looked at the center of the hall, at the dissipated remnants of the second construct still faintly visible as cursed energy residue on the floor. "The second construct was designed to be irregular. The instructor knew your failure condition from your file."
Kaito had figured that. He hadn't said it aloud because saying it changed nothing about the outcome.
"Then the session wasn't about the construct," Kaito said.
"No." Megumi's voice was flat and precise. "It was about what you do when the failure condition is triggered."
They both looked at the instructor.
She finished writing, capped her pen, and looked up with the expression of someone who had gotten what she came for.
"Good session," she said. "You're dismissed."
She left without further comment, which told Kaito nothing useful about what she'd written and everything useful about how she intended to use it.
The hall was quiet.
Megumi picked up his jacket from the floor where he'd set it before the session and pulled it on with the economical movements of someone who had somewhere to be and was deciding how quickly to get there.
At the door, he stopped.
He didn't turn around fully, just enough to indicate he was choosing to speak rather than leave.
"The containment reflex," he said. "When it activated — the construct hesitated."
"Yes."
"That's not a liability." A pause. "That's a different technique from the anchor. You have two applications and you're treating them as one problem."
He left.
Kaito stood alone in Training Hall B with the scored floor and the newer plating on the walls and the faint residue of cursed constructs in the air, and let Megumi's assessment settle into the part of his mind that was still running Gojo's question on a slow loop.
What is the space for.
He had thought the answer was in his mother's files.
Maybe it was also in the second construct's hesitation. In the four seconds of the first engagement. In the specific way his technique behaved when he stopped forcing it toward combat applications and let it do what it wanted.
His cursed energy moved at his palm.
The room-shaped outline. Patient, as always. Present, as always.
He looked at it properly this time, the way he'd looked at the courtyard structure — not managing it but observing it.
It wasn't waiting for permission to become a weapon.
It was waiting for him to understand that it had never been one.