The possibility occurred to Takami one evening while he was keeping Shin company during an after-hours training session in the workout room.
"Shin," he said, glancing from his laptop to the linebacker on the floor, "do you have prosopagnosia?"
Shin paused on what must have been something like his two hundredth sit-up and fixed Takami with a confused look. "I don't know. What is it?"
Takami pushed his glasses up his nose. "Face blindness." He went back to typing up his essay. "It's a disorder of face perception where the ability to recognize faces is impaired, while the ability to recognize other objects may be relatively intact."
Shin took a moment and four sit-ups to absorb this. Then he stopped, hands on the floor, and turned to look up at Takami with an expression Takami recognized as "I'm waiting for you to tell me what that's supposed to mean to me."
"You don't recognize people by their faces," Takami pointed out. "I was wondering: can you? Do you default to differentiating between people by muscular structure because you can't distinguish facial characteristics?"
Shin appeared to consider this for roughly half a second; then he flipped over and started doing pushups. Two in, he paused to volunteer "I don't know," and continued.
Takami sighed. He shook his head and went back to his essay…but this was going to bother him. He drummed his fingers on his knee; finally, he stood up and walked over to the wall upon which Wakana had taped an array of photos from the year's games and practices. He ran one finger along the wall under the photos, looking…eventually he found two photos and took them down.
He walked back over to where Shin was still industriously doing pushups and squatted on the floor, dropping one of the photos under Shin's face. "Who's that?" he asked, tapping the photo in case Shin was too busy muscle-building to have noticed.
Shin slowed, then stopped entirely, focusing on the photo with something approaching curiosity. It was a picture of Sakuraba's face from the chin up, taken sometime last month on the bus to an away game.
"I don't know," Shin eventually concluded, though his voice suggested he was either mildly perturbed about it or thinking about something else that was mildly perturbing, possibly relating to the fact that Takami was interrupting his workout; there was no way to tell.
Takami scooped the photo off the floor and put the other in its place. "How about that?"
"That's Sakuraba," Shin said shortly, as if he'd be an idiot for not knowing, and went back to his pushups. It was Sakuraba, all of him from the knees up, holding a bottle of water after practice.
Takami adjusted his glasses, thinking. Interesting. He pointed to the cropped arm of an anonymous teammate to Sakuraba's left. "Whose arm is that?"
"Mayamura's," said Shin, without pausing.
"Interesting," said Takami. At this point, Shin turned his head to one side and gave Takami a look that suggested he thought his teammate was being rather strange, so Takami picked up the photo and went to tape it and its partner back on the wall where he'd got them. "Well, at least we know that if you're ever mugged by masked marauders, you'll be able to identify them without fail," he said brightly, heading back to his laptop. "Assuming you don't beat them to a pulp on the spot and drag them to the police station yourself, that is."
One two, one two, went Shin's pushups. "What makes you say that?" he inquired, only faintly out of breath.
Takami rolled his eyes under the obscurity of glinting glasses slid back up the bridge of his nose and tapped out a closing sentence on his essay. "Never mind."