Palms touch iron. The stair learns manners.
"Ribs first," Iruka adds, voice even. "Ankles honest. If your hand leaves the rail, you pay with five at the alcove. Begin."
Naruto mimes a porcelain bowl at collarbone height. The invisible weight fixes his posture without speeches. Izayoi sets behind the second pair - anchor where problems try to live. Hinata takes the second tread, half a pace to the side, eyes ordinary, one word on a leash in case it buys more than it costs.
The first tread accepts them. Wood complains once and then remembers how to be floor. A boy ahead puts too much heel on the outside edge. The rail catches more pride than mass. Iruka says, "Stop," and the stop lands cheap - no drama, no echo - then they go again.
"Palms visible," Iruka says, keeping cadence. "Shoulders smaller. If you cannot fix a thing, you buy time with stillness and sell it back at a profit."
Naruto meets tread three - the turn where most plans get loud. He keeps ribs as hinges and shoulders as furniture. The bowl does not tip because the bowl is an idea that will not apologize for existing.
A strap peeks out from a bag on the inner turn, hungry for ankles. Izayoi feels it with the back of his knuckles and tucks it under leather as if tidying a room that belongs to someone else. He never looks down. Looking down spends signal.
"Good," Iruka says. "Front pair - count treads quietly. Back pair - breathe on the rail. Class - share the same spine."
They descend. A wheel squeaks on the floor below - small supply cart - a reminder from earlier becoming new weather. The squeak wants to sell the idea that attention has to move where sound points. Izayoi declines the offer. Naruto almost buys, then hears his own breath and returns change to his chest.
"Choose," Hinata says, one word, when the turn asks for an early decision. Naruto makes it early. The rail never needs to complain.
"Half switch," Iruka says, a lane farther up, where he can test without tripping. "On my count - switch which hand owns the rail. Ribs do the work. Ankles declare their honesty. Ready. One. Two. Switch."
Hands cross clean. The invisible bowls survive. Shoulders remain unremarkable. Izayoi notes Naruto's left palm trying to get proud and makes his own switch smaller in Naruto's periphery. Pride forgets to grow.
They reach the lower landing. A teacher emerges from the staff room with a stack of folders and the face of someone already late by a small amount. She meets the turn wrong and then corrects - eyes up, rail ignored, weight honest enough. Izayoi prepares to receive without pose. Not needed. Good.
"Up again," Iruka says. "Same rules. Ribs only. Palms promise. If a civilian appears, you pay by waiting unless waiting will break them. Then you receive."
They reverse. Stairs climb differently than they descend. Ankles ask new questions. A girl two ahead tries to wear speed on the outside of a foot and the rail tells her no. She pays with a half stop that looks like respect rather than fear and continues.
Naruto's invisible bowl wants a salute on tread five. He does not salute. The bowl is not a flag.
"Breathe before," Iruka says, so everyone can borrow the line.
They pass the landing window. Light makes rectangles on the wall and reminds the class how rooms used to be easy. Hinata's hand loosens a fraction - not from fatigue, from precision - and retakes its place.
"Again with the wheel," Iruka says, and the cart chooses that exact second to return with new squeak. "This time cart gets priority. Palms promise. Ankles stay home."
The cart owner looks up and tries to smile with a job in his hands. Izayoi shrinks his presence by the width of a coin wherever the cart pretends to own the corner. Naruto lets ribs smooth the difference and the bowl chooses not to fall.
"Good," Iruka says. "Now - two at the landing - no talking - one stop each. We buy the cheap version on purpose."
They stop. They go. The landing learns that pauses can be planned.
"Switch to single file," Iruka adds. "On the inside of the rail. If you feel crowded, your first answer is a smaller shoulder, not a faster foot."
A first-year from another class approaches from below with a paper tower that would not survive parachute tests. He takes the inside far too close to the rail and breathes as if breath can apologize for geometry. Naruto gets there first and pays with stillness. Izayoi receives the misstep with the lightest forearm on a sleeve and returns a boy to his own lane without letting a story be born. Papers keep their stack. Stairs keep their tone.
"Five minutes," Iruka says. He is counting for the cap, not for the class's ego. "We hold the line."
They climb another pass - descend another - the stairs becoming a place where insults like slick treads and lazy ankles forget how to live. A thread of water from some cup on some day decides to find tread four. Hinata sees it, calculates someone else's foot, and says nothing because saying nothing is cheaper than an unnecessary word. Izayoi reads her silence and plans his foot for the dry inch anyway. Naruto puts his palm on iron with honesty that finally looks like comfort and not performative innocence.
"Variation," Iruka says. "No-look pass at the turn. Teacher incoming."
At the turn, a math teacher arrives with a chin full of thinking and a rail hand that belongs to someone else. Izayoi sells him courtesy at cost. Naruto learns that he can narrow while making room and still keep the invisible bowl proud. The no-look pass happens without anyone no-looking on purpose. It simply lives.
"Last full minute," Iruka says. "We do not get clever because the end exists. We get smaller."
The stairwell agrees. Footsteps sync to safety rather than speed. Ankles tell truth in chorus. The rail becomes a promise rather than a rule.
Then noise changes.
Footsteps multiply hard from above - fast, light, clustered. Laughter inside a shush. A visiting group that ignored a schedule or outran its escort - small bodies, too many elbows - a teacher voice saying "slow" at the wrong distance.
Iruka's head turns the amount a supervisor is allowed. "Hold," he says, calm blade. "Palms stay. Ankles stay. Row one stops at the landing. Row two will not attempt to pass pride with speed."
The class binds to the rail like smart rope. Naruto's bowl lowers a finger width and stays unspilled because it does not exist. Izayoi shifts half a tread to where incoming will learn to be patient without meeting a wall.
A courier appears from below at the same time, crate hugged to ribs, eyes up but too far away to help today. Stairwells believe in jokes.
"Receive if needed," Iruka says, not louder, just nearer.
The first of the visiting group rounds the upper corner - three kids in festival shirts, a fourth trying to lead by noise, a chaperone soft and late. They see the stopped line and almost win a collision with their own plan.
"Small," Hinata says to no one and everyone, voice aimed at breath level, not ear level.
It buys enough.
The lead kid checks speed with both hands on the rail like a lesson being auditioned. The second piles into the first and rebounds into a shoulder that belongs to the third and then finds iron. The fourth nearly steps long on the outer edge.
Izayoi moves the soft part of his forearm the distance that rescues dignity without announcing rescue. The fourth's foot chooses the flat part of tread instead of its pride. Naruto does not look. He keeps his palm where rules live. The courier three treads below re-prices his climb and waits two breaths.
"Good," Iruka says. "Landing line holds. Group passes when they have learned to be slower than the rail."
The chaperone meets Iruka's eyes and reads the posture there - not anger, not indulgence - policy. She places her own palm on iron, says, "Hands on rail," to her kids, and turns a noise into order with one borrowed tool.
Space in the stairwell remembers it is communal. The visiting group goes by. The courier nods up, waits for permission with better manners than before. Iruka lifts two fingers and the courier accepts the signal as if it were law.
"Thirty seconds," Iruka says. "We close the cap clean. No victory laps. Honest ankles all the way to the alcove."
They flow again. Treads behave. The rail breathes a little with all the palms but does not complain. Hinata tightens her watch on feet at the back because fatigue writes lies in ankles before it becomes speech in shoulders.
A second pulse of footsteps drifts from above - older, heavier, trying to be careful and failing at the timing - maybe a class that got dismissed too fast. Iruka hears it and measures the distance to collision, to crowding, to pride.
"Hold at the landing," he says, picking the cheaper future. The line stops. The stair holds them all without anyone performing for it.
The second group turns the upper bend, meets a waiting line that does not apologize for waiting, and decides to be patient because patience is contagious at this density.
"Seven," Iruka says, eyes on the clock that is not present and yet exists because he made it. "Cap reached."
He could end there.
He listens instead - one beat - for the next problem that would make ending expensive.
He hears it.
More steps. More voices. A teacher asks for order with a tone that does not yet own the air. The second group spreads at the shoulders where the landing narrows. The chaperone is late again for other children.
Iruka points once - a small, surgical gesture. "Hinata," he says without raising. "Byakugan - now."
Her inhale is the start of the sight. The veins around her temples will rise on the next breath.
The stairwell holds itself on that single edge between ordinary and instrument.