Seiko 7F18-9A00 'Celestial' Quartz — Moonphase + Sun Phase, 1988 (Ref. SEP008J)
$ 171.6
Description
Seiko 7F18-9A00 'Celestial' Quartz — Moonphase + Sun Phase, 1988 (Ref. SEP008J). December 1988 production with full caseback provenance. A Seiko 7F18-9A00 — the late-1980s 'Celestial' multi-function quartz dress watch (also marketed as Ref. The caseback engraving (7F18-9A00 R / 8D0142) decodes as December 1988 production. ). A Seiko 7F18-9A00 — the late-1980s 'Celestial' multi-function quartz dress watch (also marketed as Ref. SEP008J). The dial layout is what collectors seek out: four symmetric subdials with a true moonphase at top, a separate sun-phase / day-night indicator at right, date at left, and day-of-week at bottom — Seiko's unusual 'double phase' complication, paired in a Patek-symmetric subdial arrangement. The caseback engraving (7F18-9A00 R / 8D0142) decodes as December 1988 production. Fresh battery installed; all four subdials advance correctly via the corrector pushers at 2 and 4. Double-phase complication: Both a true moonphase subdial (top) and a separate sun-phase / day-night indicator (right) — two half-discs with matching disc art, the moon emerging from the blue night-sky disc on the upper subdial, and the sun riding the day-cycle disc on the right subdial. This combination is the rare Seiko-7F18 signature; no other quartz dress watch of the era pairs the two phases as separate complications. Seiko Caliber 7F18 — collector-grade quartz: Seiko's late-1980s flagship dress-quartz multi-function caliber, regarded for its accuracy and for the unusual subdial layout. Collector demand for the 7F18 references — particularly the 7F18-9A00 'Celestial' / SEP008J — concentrates around dial condition; pristine dials command meaningfully more than aged or stained ones. This example's dial is in exceptional condition: crisp white field, gold Roman numerals + pearl markers sharp, blue moonphase disc deep with no fading, both calendar subdials fully legible. Period detail and provenance: 35mm gold-plated case (case body shows surface wear at the lug edges and case sides consistent with 35+ years of use; the dial and movement are the value drivers, not the case finish). Mineral crystal clear. Caseback engraved 'SEIKO • WATER RESISTANT • STAINLESS STEEL BACK • 7F18-9A00 R • 8D0142' — the serial 8D0142 decodes as December 1988 production (Seiko date code: 8 = year ending in 8, D = December). Original-style brown leather strap. Condition: Dial is exceptional — crisp white field with sharp gold Roman numerals and pearl markers, deep blue moonphase disc, intact sun-phase disc, both calendar subdials fully legible. Mineral crystal clear. Gold-plated case shows surface wear consistent with daily-wear vintage condition — base metal showing through in places at the lug tips and case sides; the case is the third priority after dial and movement. Original-style brown leather strap shows visible wear from vintage use. Caseback engraving '7F18-9A00 R / 8D0142' legible. Fresh battery installed; movement runs cleanly; all four subdials advance correctly via the corrector pushers. For the vintage-Seiko collector specifically hunting the 7F18 caliber with the double-phase moon+sun complication. The dial is the value variable on this reference and this example presents exceptionally well — case wear is the expected vintage compromise. December 1988 production with full caseback provenance. Included: Watch on original-style brown leather strap. Fresh battery. No box, no papers.
