The Rotation A private register · 2026

For iPhone · on the App Store

Your watches keep the time.
The Rotation keeps the record — and checks the rate.

A private register that files the serial, tracks the wear, and listens to the movement through your phone. +3.1 s/d today, and every day since the last service.

Hear how it’s running Download on theApp Store The film 0:45
The bench · a seeded traceResting
Rate—
Beat error—
Amplitude—
A seeded trace, read by the page’s own timing engine — one watch, as the bench would show it. Nothing is heard here; the demo below listens.
Administration
The collector’s entrance

The film

The register, in forty-five seconds.

What is therotation.ai? — a drawn watch movement turning above the question, the first frame of the house's film.
Drawn in the house · 45 seconds · silent

What you own, what you wear, what you want — and how each watch is running. One register, kept on your iPhone, with two instruments the phone already carries.

The film, in words
  1. What is therotation.ai? A question we keep being asked.
  2. A private register for a watch collection, kept properly. What you own. What you wear. What you want.
  3. Photograph the watch. The Eye names it. An AI model — Claude, by Anthropic — reads the dial against the catalogue. Nothing is filed until you confirm it.
  4. The serial filed. The wear logged. One file per watch, and every field yours to leave empty.
  5. Two doors. The bench, and the compass.
  6. Then it reads. Rate, beat error and frequency — filed with the watch, in its record.
  7. And it keeps the sound. Twenty seconds of the watch’s own voice, kept with the reading — to hear again a year from now.
  8. A magnetised hairspring sticks to itself. The balance swings short, and the watch gains seconds a day — sometimes minutes.
  9. The Observatory checks it with the phone’s own compass. No instrument but the one already in your pocket.
  10. Lay the phone flat. Bring the watch slowly to the compass. The field moves, or it does not.
  11. Magnetised — 42 µT. A watchmaker’s demagnetiser takes seconds, and it is the likeliest reason for a rate that has jumped.
  12. The hunt, wound toward the next piece. Name the watch you want, set a target, and wind the reserve as you put money aside.
  13. The month, accounted for. Days logged, what was worn, what stayed in the box, what moved in value. Written for one reader.
  14. A register kept properly. The Rotation, for iPhone. For watch collectors.

The Eye

Photograph the watch. The Eye names it.

Drawn in the house: a Reverso held in a camera's viewfinder, and beneath it the app's question, Is this the watch? — best match, Jaeger-LeCoultre Reverso Classic, with its reasons and the act Yes, fill the form.
Drawn in the house · the Eye’s own words

A photograph of the dial is the quickest way to file a watch. The Eye reads the brand and model for you to confirm, checking what it sees against the catalogue. It can be wrong, so nothing is filed until you confirm it.

  1. iThe photograph is clear enoughBest with the dial in focus, in its own light.
  2. iiLooking for the brand and modelThe printed name, the hands, the case, the numerals.
  3. iiiChecking against the catalogueEach candidate held against the references it could be.

Is this the watch? You confirm the best match, choose another, or enter the details by hand. Nothing is filed until you do.

An AI model — Claude, made by Anthropic — reads what you photograph. No person reads it. What the AI touches

The timegrapher

A timegrapher, on this page.

Hold your watch to the phone. Ten seconds of listening gives the rate in seconds a day and the beat error in milliseconds. Nothing you record leaves this page.

Quiet room. Case back or crown against the microphone. Keep still.

Kept in the register, this becomes a line over months.

Any figure shown on this site is one watch on one day, measured on a phone — on the figures we publish.

The compass

When a watch suddenly runs fast.

Magnetism is the commonest reason a mechanical movement loses its accuracy overnight. A phone case, a laptop lid, a handbag clasp: the steel of the movement keeps a remanence, the hairspring’s coils stick to one another, the balance swings short, and a watch that kept two seconds a day starts gaining twenty. Nothing looks wrong.

The Observatory’s magnetism room, drawn: a phone lying flat on the bench, its compass marked beside the charging port, a watch held just beyond its foot, level with the glass, the compass needle pulled off north and the field reading 42 microtesla — magnetised.
Drawn in the house · 25 seconds · silent

The iPhone app checks for it with the one instrument already in your pocket.

  • ILay the phone flat, screen up.On wood or stone — not on a speaker, a cable or a steel desk.
  • IIKeep the watch away for two seconds.The compass takes its baseline. If the room is noisy it says so and asks again.
  • IIIBring it slowly to the compass, where the app shows it, and away. Then turn it over, and again.Never touching the phone. The second pass tells the watch’s steel from magnetism.

The verdict

The compass reads the field beside the watch, twice: dial up, then dial down. What swings the other way when the watch is turned over is a magnet; what stays is the steel of the movement, which bends the Earth’s field on its own and is named as steel. Under six microtesla, nothing the phone can feel. Past twenty, magnetised: a watchmaker’s demagnetiser takes seconds, and it is the likeliest reason for a rate that has jumped. Apple keeps the compass in a different place from one iPhone to the next — at the foot, beside the charging port, on most 16s and 17s — and the app shows each phone’s own. Where it lies under the glass the figures file with the next bench reading, so the record says whether the watch was magnetised when it was heard; read from beyond an edge, the answer is shown as provisional and kept off the record until the house has calibrated that placement. And when a reading steps twenty seconds a day from where the watch usually stands, the bench itself says to check.

A balance wheel drawn from above, its hairspring an Archimedean spiral in a gilt hairline, the two outer coils pulled together and touching, marked in ruby.
The balance, from above
The watch held just beyond the phone’s foot, beside its compass, the needle pulled off north, the field in red, and the figure: 42 microtesla, magnetised.
The needle’s answer — 42 µT
The same watch afterwards: the needle at rest, no field drawn, and the figure 2 microtesla, quiet.
The same watch, afterwards — 2 µT
Heading—
Field, from the film42µT
On a phone, the needle follows the phone’s heading as you turn, from the motion sensor the browser allows after one tap. The browser gives no magnetometer, so the field figure is the film’s. Nothing leaves the phone; nothing is kept. The app reads the field itself.

The rooms

One register, six rooms.

Today: the house's movement turning, the thought of the day, and the register's figures — seven watches, sixty-eight days logged.
Today

The day’s page: a thought, the figures, and what you wore.

Add a watch: How would you like to begin? Photograph the watch, choose a photo you already have, enter the details, or ask the Registrar.
Add a watch

A photograph, the details, or the Registrar in your own words.

The collection: the Reverso Classic on the wrist today, and one card per watch with its calibre, its days at rest and its rate.
The collection

One file per watch, the rate and the wear on every card.

The bench: a Jaeger-LeCoultre Reverso Classic chosen, its calibre drawn, and the instruction Rest the watch on the microphone.
The bench

Rest the watch on the microphone. It reads the rate.

The standards: the collection ranked at the bench by rate, with each watch's beat error and beat.
The standards

The collection, ranked by how each watch is running.

Magnetism: Is it magnetised? A guided check in about thirty seconds, and where the compass sits on this iPhone.
The compass

Is it magnetised? A guided check in about thirty seconds.

The screens as the app draws them

What the register is for.

The record a claim asks for

Reference and serial. What you paid and when. The last service and the interval you keep. A value in your own currency. The things you are asked for on the worst day, written down long before it.

Kept on your phone first

The register is written to your iPhone first and follows to your other devices second. Nothing is written to your record without you, and your photographs train nothing. What the AI touches ›

No marketplace

Nothing is listed, nothing is brokered, and no commission exists. The register earns nothing when you sell — so it has no opinion about whether you should.

What a record holds

One file per watch, kept on your own device first. Every field is yours to leave empty.

Membership

The first week is free.

Seven days free

The Rotation is free to download, and from version 1.1.2 your first three watches are kept free — with their photographs, the Eye within a daily allowance, their wear log, the bench and the compass. The whole collection, the wishlist’s photographs and Eye, the bench’s voices, the Registrar and the importer open with a membership, monthly or yearly, through the App Store. Whatever you file stays yours to read and to export, always, member or not.

Download on theApp Store

The free week is Apple’s, offered once to an Apple ID on each plan. A free trial becomes a paid membership when it ends unless it is cancelled at least a day before, in your Apple ID settings. The price in your country is on the App Store. Terms