Ishizaki's Calculations

In the week following the swimming lesson, Kanzaki Toru noticed something amiss.

A male student from Class C had been hovering around Sudo.

The guy had dyed, sandy-yellow hair and was of slightly above-average height for a boy. He walked with a pronounced sway in his shoulders and always looked at people with a sidelong glance. Kanzaki had seen him in the hallway twice—the first time during a break, when he was loitering outside the Class D door and spoke a few words to Sudo after he stepped out; the second time was after school, when he emerged from the back door of the gymnasium with Sudo and Yoshida following behind, all three of them looking rather grim.

He didn't know the guy's name. But judging by the Class C badge on his uniform, he wasn't from Class D, nor did he look like the two second-years who had cornered Yoshida behind the gym earlier.

During the Wednesday lunch break, Kanzaki went to the rooftop.

Ever since he had discovered the pried-open door, he had been coming here once or twice a week. The rooftop offered a wide view, allowing him to see the playground, the entrance to the shopping mall, and the direction of the old school building simultaneously. The rusty folding chair was still in its place; it hadn't gathered any dust recently, and there was a faint shoe print under the armrest—the tread of a sneaker, and not a very large size.

Someone had been here recently. It wasn't Ishizaki; Ishizaki's feet were larger than this. It wasn't those two second-years either—the buzz-cut one and the bald one hadn't appeared again since the incident at the old school building. The owner of this footprint was, in all likelihood, someone else.

He committed this information to memory and walked to the railing to look down.

On the playground, Sudo was playing soccer with Yoshida. The sandy-haired boy from Class C stood at the edge of the field, arms crossed, his gaze tracking Sudo's movements. It wasn't the look of a casual spectator; it was a stare—a focused, evaluative gaze. A moment later, Sudo scored a goal, turned, and waved at the guy, shouting something. The boy grinned and gave a thumbs-up in response.

Kanzaki opened his terminal and typed a line into his notes: "Sandy-haired boy, Class C. Contacting Sudo. Need to confirm name."

Before the Friday homeroom, Chabashira stood on the podium and scanned the classroom. In her usual businesslike tone, she announced that the new study group arrangements would be posted next Monday. Some groups would include members from different classes, and the specific groupings would be posted on the bulletin board on the first floor of the academic building at that time.

Cross-class groups. The four words fell into the quiet classroom like a pebble dropped into a still pond. A few girls in the front row began to whisper, while Sudo and Ike Kanji exchanged glances in the back. Horikita Suzune didn't turn her head, though her pen tip paused on her notebook.

Kanzaki noticed something else—Horikita's brow twitched imperceptibly when she heard the word "cross-class." Horikita was acting strangely today. From the moment she walked into the classroom that morning, her back had been straighter than usual. After sitting down, she kept her hands clasped on the desk without turning a single page of her book; she looked like a taut string. After Chabashira mentioned the cross-class groups, that string seemed to tighten another notch.

After school, he went to the gym.

Sudo was there, as expected. He was lying on the bench press with two large iron plates on the barbell, significantly lighter than the weight he had used last time. Two people stood nearby—Yoshida was leaning against the wall drinking water, and the other was the sandy-haired boy from Class C. Up close, the guy looked even leaner than he had from a distance; he wore a metal chain around his wrist and carried a frivolous expression.

"One more!" the guy said, clapping his hands while squatting beside the bench.

Sudo gritted his teeth and pushed the barbell up, his arms trembling slightly. He finished the final rep and racked the bar with a loud clatter. He sat up, panting heavily, and wiped the sweat from his face with a towel.

"Not bad, Sudo! Your stamina is no joke!"

"Of course," Sudo grinned. "But what's with the sudden interest in working out today?"

"Just looking for some tips. The basketball team's physical training is getting more and more brutal." The guy stood up and rolled his shoulders. "By the way, have you thought about that thing?"

Sudo's expression shifted. It wasn't anger, but hesitant excitement. "...I'll think about it some more."

The guy smiled, patted Sudo on the shoulder, and turned to see Kanzaki standing at the entrance. His gaze lingered on Kanzaki for a moment—not a casual glance, but a quick, precise, top-to-bottom assessment. Then, he nodded at Sudo and brushed past Kanzaki, his shoulder nearly grazing his.

Yoshida walked over and whispered, "That guy's name is Kondo, from Class C. He's been coming around to play ball with Sudo a lot lately."

Kanzaki nodded.

Over the next few days, he began using his spare time between classes to observe the flow of people around the Class C classroom. He needed a name, a definitive face to verify the suspicions that were becoming increasingly clear.

On Tuesday afternoon, he ran into Horikita in the hallway. She was carrying coffee and walking faster than usual; she nearly bumped into his shoulder before pausing. When Kanzaki asked her about Kondo, she thought for a moment and indicated that she also needed to go back and confirm some things before getting back to him with information.

That evening, his terminal received a short message from Horikita. The attachment was a screenshot of the student directory. The person in the photo was indeed the sandy-haired boy. His name was Kondo Reion, Class 1-C. The remarks column contained a brief note: "Grouped with Ishizaki Daichi, peripheral member of Ryuen Kakeru."

Ryuen Kakeru. The de facto leader of Class C. In the few times Kanzaki and Horikita had exchanged intelligence, this name had been highlighted by Horikita twice. The first time was when analyzing the potential risks facing Class D, and the second was when she was organizing a list of core figures from each class. This person was not one for direct confrontation, but was highly skilled at setting traps—using information asymmetry and human weaknesses to pierce an opponent's defenses.

On the third day, he met Horikita behind the school building. The setting sun cast long shadows across the dusty concrete path. She leaned against the wall, arms crossed, and pieced together all the clues she had gathered regarding the Sudo incident. Kondo was responsible for approaching Sudo and probing his bottom line; Ishizaki was responsible for coordinating and passing messages. The two second-years behind the gym last semester hadn't appeared by chance—they were likely the first wave of pawns Ryuen had released to test Class D's reaction. Kondo was also in the basketball club, the same as Sudo. Ryuen's choice of him to approach Sudo was calculated with precision: members of the same club naturally possessed a foundation of trust.

"Once Sudo falls, Class D loses one of its most important sources of physical strength in competitive events. Kondo isn't acting alone—behind him is Ishizaki, and behind Ishizaki is Ryuen. Ryuen is laying the groundwork, and the target was never Yoshida from the start."

By the time Horikita finished her last sentence, the twilight had deepened until only a faint glimmer remained in her pupils. Her judgment was in complete agreement with the conclusion he had reached: Class C's intent was not about the outcome of an individual conflict, but about dismantling the internal combat structure of Class D.

If one person from Class D were expelled, the entire class would have points deducted. And Sudo was the easiest person in Class D to provoke, and the easiest to lure into a trap.

Kanzaki looked up toward the direction of the rooftop.

Ryuen—the name sank into the darkness like a reef that hadn't yet surfaced above the water.