CALIBER/browser
CORPUS EXPORT · 12269 calibers · 59387 family views · round round/2026-09-08Compiled from app/public/data/ · corpus 70c0140eba.
Family treeSeiko 6R15 — Heritage family: 3 calibers, 2 sourced lineage links.Drag to explore.
100%drag to pan · hover a caliber to isolate its line · scroll the page normallyopen the full family view →
derived fromderived fromSeiko 4R36 / NH36 — open caliber pageSeiko 4R36 / NH362011Seiko Instruments Inc. (SII)1 exec · grade ?Seiko 6R15 — the caliber this page is aboutSeiko 6R152006Seiko Instruments Inc. (SII)1 exec · grade ?Seiko 7S26 — open caliber pageSeiko 7S261996Seiko Instruments Inc. (SII)1 exec · grade ?
accepteddisputed
Sense of “family”Heritage · 3Everything (debug) · 3Parts cluster (Jules Borel sense) · 1Manufacturer-internal (Ranfft sense) · 1Based-on star (WatchBase sense) · 3Open the full family view →

movement

Seiko 6R15

Seiko Instruments Inc. (SII)introduced 2006design:seiko-6r15compare specs · 3
bounding evidence — no range is drawn on the era axis
not after 2011
Seiko 4R36 / NH36 · introduced 2011 (sourced)you cannot derive from what does not exist · → derived from · rule IR-2 · depth 1 · acceptedthe anchor's own source
not before 1996
Seiko 7S26 · introduced 1996 (sourced)you cannot derive from what does not exist · ← derived from · rule IR-2 · 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
Seiko 6R15
movementproducer: Seiko Instruments Inc. (SII)
IIDesignations — 0 names

No designation is recorded for this design yet.

IIIExecutions — 1 article

No source in this corpus states which grade any Seiko 6R15 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:seiko-6r15/unknown

Specifications

PropertyValueScopeStatusSources
Mainspring alloy
mat.mainspring_alloy
Spron 510—accepted
Power reserve (typical)
power.reserve_typical_h
50 h—accepted
Introduced
prod.intro_year
2006—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.

Ancestors · 1

Where this construction came from. Read up the arrows.

Descendants · 1

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

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.

Sources

  1. 1
    Caliber Corner
    https://calibercorner.com/seiko-caliber-6r15/
    curated dbtier 2retrieved 2026-08-242 facts on this pagecited, never crawled
  2. 2
    namokimods.com
    https://www.namokimods.com/blogs/namokitimes/can-you-build-seiko-mods-with-the-7s26-4r36-or-6r15-calibres-6
    presstier 3retrieved 2026-08-245 facts on this page
  3. 3
    watchuseek.com
    https://www.watchuseek.com/threads/seiko-4r36-vs-7s26-major-improvement-or-just-added-hack-hand-wind.937856/
    forumtier 4retrieved 2026-08-241 fact on this page