m
m. — runner
𝕏
Pre-dawn loop. Sealed and quiet.
証
≥ 8 km · 04:00 – 05:00 UTC
zk-9b2c…41af · ✓ verified
Zetsu · 絶 · in private practice
Run anywhere.
Run anywhere.
Prove it.
Reveal nothing.
Zetsu turns each run into a private cryptographic proof — a verifiable mark of presence that exposes none of the trace. No map. No timestamps. No identity. Just a seal that says: this happened.
01 · Manifesto
The principle is simple. Presence, without exposure.
private by default私
Your trace is yours.
The route never leaves the device. There is no cloud copy, no upload, no shared map. Strava is for sharing; Zetsu is for keeping.
provable on demand証
A run, sealed.
When you choose to, Zetsu seals the run into a zero-knowledge proof — a small mark that proves the run happened without disclosing its shape.
quiet by design静
No feed. No follow.
There is no social graph in the app. No likes. No leaderboard. The practice is the point — and the practice is private.
02 · The loop
Four moves. That's the whole app.
Begin
Open Zetsu. Press start. The phone captures GPS, accelerometer, heart rate — locally.
Run
Cadence, pace, heart-rate — held privately. Nothing transmits. Nothing syncs.
Witness
Optional anchors — public chains, paired devices, time beacons — bind the run to the world without naming it.
Seal
A single tap stamps the run with a hanko-like cryptographic seal. Share the seal — never the trace.
03 · The artifact
What you actually share. A seal, not a story.
Specimen receipt
The seal speaks for itself.
Anyone can verify: a run of at least N kilometers occurred between two public timestamps, by the holder of this key. The route, identity, and exact pace stay with you.
Coaches, sponsors, communities — they don't need your map. They need a mark.
claim≥ 8 km · between 04:00 – 05:00 UTC
circuitzetsu/v1
anchor0x4f1c…d22a
sealzk-9b2c…41af
status● verified
04 · In hand
What stays. What leaves.
Run · 0428
A clean trace.
8.42
kilometers
42:27
duration
5:02
avg pace
154
avg bpm
04:18
anchored
証
verified
zk-9b2c…41af
Captured locally. Sealed on device. Sent: a hash.
05 · Boundaries
What Zetsu will never do.
No public map.
Your route is never plotted on the internet. There is no shared layer. There is no heatmap.
No social feed in the app.
No followers, no likes, no comments. The practice is between you and the act.
No tracking pixels.
Zetsu phones home for nothing. Anonymous build telemetry can be turned off in settings.
No upsell.
One purchase. No subscription tiers gating fundamentals. The proof system is the product.
07 · Take your mark
Quiet runners,
Quiet runners,
step in.
The first cohort opens in summer 2026. Members get early access to the iOS app, a numbered hanko at launch, and an invitation to the founders' run.
Mark · 絶
Step into the practice.
Drop your email below. We'll write once when the first cohort opens — and never again unless you ask.
● Sealed
You're on the line. Watch for one quiet email when the cohort opens.
2,418 · runners on the line
08 · FAQ
Honest questions.
No. Strava is a feed; Zetsu is a seal. If you want a public log of every run, Zetsu is not for you. If you want a private record with the option to prove it, Zetsu is the instrument.
Each run becomes a zero-knowledge proof — a small cryptographic statement that asserts a property (e.g. "this device covered ≥ 8 km between two public timestamps") without disclosing the underlying data. The proof is a few hundred bytes; the trace stays on your device.
Only the claim you choose to make. There are three disclosure tiers: minimal (occurred), standard (distance + duration window), and region (loose bounding box, opt-in). You decide which seal to share.
Yes. Local export to GPX/FIT is supported. Once it leaves Zetsu, it's no longer private — that's the trade-off, and it's yours to make.
Secure Enclave + tight sensor APIs let us hold keys in hardware and capture motion without backend round-trips. Android is on the map for cohort two, once the proof system is steady.
The verifier and circuit will be open-sourced before public launch. The app is closed-source for now to protect the cohort.