CALIBER/browser
CORPUS EXPORT · 12269 calibers · 59387 family views · round round/2026-09-08Compiled from app/public/data/ · corpus 70c0140eba.
Family treeZenith El Primero 400 Z — Heritage family: 7 calibers, 6 sourced lineage links.Drag to explore.
100%overlaydrag to pan · hover a caliber to isolate its line · scroll the page normallyopen the full family view →
derived fromderived fromderived fromrevision ofrevision ofderived fromRolex 4030 — open caliber pageRolex 40301988Zenith1 exec · grade ?Zenith 3019 PHC (El Primero) — open caliber pageZenith 3019 PHC (El Primer…1969Zenith1 exec · grade ?Zenith El Primero 3600 — open caliber pageZenith El Primero 36…2019Zenith1 exec · grade ?Zenith El Primero 3620 — open caliber pageZenith El Primero 3620—Zenith1 exec · grade ?Zenith El Primero 400 — open caliber pageZenith El Primero 4…1987Zenith2 exec · grade ?Zenith El Primero 400 Z — the caliber this page is aboutZenith El Primero 400…1998Zenith1 exec · grade ?Zenith El Primero 405 — open caliber pageZenith El Primero 4…1997Zenith1 exec · grade ?
accepteddisputed
Sense of “family”Heritage · 7Everything (debug) · 7Parts cluster (Jules Borel sense) · 1Manufacturer-internal (Ranfft sense) · 3Based-on star (WatchBase sense) · 7Open the full family view →

movement

Zenith El Primero 400 Z

Zenithintroduced 1998design:zenith-el-primero-400zcompare specs · 3
bounding evidence — no range is drawn on the era axis
not before 1969
Zenith 3019 PHC (El Primero) · introduced 1969 (sourced)a revision is not earlier than what it revises · ← revision of · ← revision of · rule IR-1 · depth 2 · acceptedthe anchor's own source
not before 1987
Zenith El Primero 400 · introduced 1987 (sourced)a revision is not earlier than what it revises · ← revision of · rule IR-1 · depth 1 · acceptedthe anchor's own source

Identity

A caliber is three separate things and this reference keeps them apart: the construction, the names it is sold under, and the article a brand actually bought. A watch model points at an execution — never at a bare construction — which is why “same caliber” is almost never a complete answer.

IDesign — the construction
Zenith El Primero 400 Z
movementproducer: Zenith
IIDesignations — 0 names

No designation is recorded for this design yet.

IIIExecutions — 1 article

No source in this corpus states which grade any Zenith El Primero 400 Z was bought at. That unknown is stored as a real row rather than left blank, so it can be counted, filtered and excluded from any comparison that would otherwise assume parity.

unknownsynthetic
evidence: unknown

no source states which grade this article was bought at — this row exists so 'unknown' stays countable instead of becoming an assumption

exec:zenith-el-primero-400z/unknown

Specifications

PropertyValueScopeStatusSources
Escape-wheel teeth
esc.escape_wheel_tooth_count
20—accepted
Introduced
prod.intro_year
1998—accepted

Lineage

The same relationships as the tree at the top of this page, with their sources. An absence in a column means no source stated one.

Descendants · 0

What came from it — revisions, variants, clones, licensed copies.

None recorded. An absence here means no source stated one, not that none exists.

Related · 0

Stored in a different table from descent. A successor is not a child.

None recorded. An absence here means no source stated one, not that none exists.

Curated family labels

El Primero (Zenith)
authority: zenith7 members

Sources

  1. 1
    Monochrome Watches
    https://monochrome-watches.com/in-depth-the-history-of-the-zenith-el-primero-high-frequency-automatic-chronograph/
    presstier 2retrieved 2026-08-2411 facts on this page
  2. 2
    zenith-watches.com
    https://www.zenith-watches.com/en_us/product/defy-extreme-97-9100-9004-80-i209
    manufacturertier 1retrieved 2026-08-241 fact on this page
  3. 3
    Monochrome Watches
    https://monochrome-watches.com/history-rolex-daytona-chronograph-1963-in-depth-review/
    presstier 2retrieved 2026-08-241 fact on this page
  4. 4
    Monochrome Watches
    https://monochrome-watches.com/zenith-chronomaster-2-the-next-big-step-forward-for-the-el-primero/
    presstier 2retrieved 2026-08-241 fact on this page