That afternoon, Teacher Mizuno did not hand out papers first.
She led East Corridor Group Two to the end of the hallway and had them stand by the door, watching how others went in and out. The door between the regular classroom and the East Corridor opened and closed, and the sounds of footsteps, chairs scraping, and pages turning leaked bit by bit through the crack. Today's lesson, the teacher said, was neither lining up nor being quiet. It was borrowing a door.
"The door isn't yours," she said. "But you'll pass through it. If you're passing through, you need to know when to let others go first, when to go after them, when to hold the door a little, and when not to slam it shut."
Kiyo raised his hand as soon as she finished. "Can doors feel pain?"
Teacher Mizuno looked at him. "Try slamming it and see if it hurts."
Kiyo immediately pulled his hand back. "Then I'd better not try."
East Corridor Group Two formed two lines and took turns passing through the doorway. Who went first, who went after, who paused, who turned sideways to make a little room—all of it counted as part of the day's exercise. When Che went through, he drew his shoulders in slightly instead of taking up as much space as he usually did. The doorframe was old, its edges still lined with wooden splinters polished bright by countless hands, as if it too had endured endless people borrowing their way through.
When it was Kiyo's turn, he moved too fast and too urgently, nearly catching his backpack strap on the doorknob.
“Stop,” Teacher Mizuno said.
Kiyo froze.
"When you go through a door, you're making way for the room, not picking a fight with the door."
"But the door