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The Encyclopedia of Horology

Wristwatch · Automatic alarm wristwatch

Seiko Bell-Matic automatic alarm wristwatch, ref. 4006-6027

Partially verified

This is a vintage Seiko Bell-Matic automatic alarm wristwatch, reference 4006-6027, dated by the seller to April 1973. It is fitted with a 17-jewel mechanical movement featuring an automatic winding system for timekeeping, a manual-wind alarm function, and a day/date complication. The stainless steel cushion-shaped case measures 39 mm in diameter and includes an outer blue enamel bezel insert. Its dark blue dial presents silver-tone baton indices, a day-date aperture at 3 o'clock, an internal rotating alarm bezel ring, and a red central seconds hand.

Oblique view of the Seiko Bell-Matic 4006-6027 cushion case, dial, and bracelet
Oblique view of the Seiko Bell-Matic 4006-6027 cushion case, dial, and bracelet — Secondhand Horology. Rights pending — permission not yet requested. Original source

Catalogue identity

Source
secondhandhorology.com
Category
Wristwatch · Automatic alarm wristwatch
Maker / attribution
Seiko
Reference
4006-6027
Catalogue / lot identifier
WA-3572
Source-reported date
April 1973
Country
Japan
Source-reported serial
340178

Source-reported attribution and specifications are not independent authentication. A listing does not establish present ownership, current display, availability or permission to reproduce.

Object description

Case and Exterior

The timepiece features a stainless steel cushion-shaped case measuring 39 mm in diameter, with a lug-to-lug measurement of 43 mm and a thickness of 13.4 mm. The case features a radial brushed finish and is paired with a blue enamel bezel insert.

The case back is marked 'Seiko Time Corp. SEIKO Stainless Steel 4006-6027 Water Resistant 340178 Japan A'. The watch is equipped with a stainless steel fold-over clasp bracelet.

Evidence for this section
  • “Cased in a robust 39mm cushion case, all in stainless steel.”
  • “Radial brushed finish case and the super nice blue enamel bezel insert.”
  • “Case Back Signed: Seiko Time Corp. SEIKO Stainless Steel 4006-6027 Water Resistant 340178 Japan A”
  • “Case Diameter 39”
  • “Case Lug to Lug 43”
  • “Case Thickness 13.4”
  • “This watch also comes with the original Seiko all stainless-steel fold over clasp bracelet”

Dial and Complications

The watch features a dark blue dial with silver baton hour markers, luminous dot accents, and silver/luminous sandwich hands. A red central sweep seconds hand is present, alongside a day-date aperture located at 3 o'clock.

An internal rotating bezel ring is used for the alarm function, which includes a luminous indicator. The date quickset is operated via a pusher at 2 o'clock, while the day indicator is set by rotating the time between 22:30 and 1:00.

Evidence for this section
  • “original dark blue dial featuring silver baton hour markers, luminous dots, white minute/second track, silver/luminous sandwich hands and a red sweep second hand.”
  • “brushed blue internal rotating bezel ring with the red/luminous alarm indicator.”
  • “day sets by changing 22:30-1:00 / date quicksets with button at 2 o’clock”

Movement and Documentation

The watch utilizes an automatic movement with a manual-wind alarm function and 17 jewels. The listing provides inconsistent information regarding the specific caliber, referencing 'Cal. 4006A' in the description text and 'Cal. 4005A' in the technical specifications section.

The movement has not been independently verified.

Evidence for this section
  • “It is a self-winding alarm watch powered by an original Seiko automatic movement caliber 4006A”
  • “Movement: Seiko Time Corp. SEIKO 17 Jewels Cal. 4005A”
  • “automatic, manual wind alarm, 17 jewels”

Open research questions

  • Does the serial number 340178 correspond to an April 1973 production date?
  • Why does the seller list both Caliber 4006A and 4005A in the same listing?
  • Is the enamel bezel insert original to this reference?

Source evidence

Recorded claims and source quotations for Seiko Bell-Matic automatic alarm wristwatch, ref. 4006-6027
FieldSource-reported valueSource quotation
Reference4006-6027“This is a vintage Seiko Bell-Matic, an automatic alarm wristwatch, reference 4006-6027”
Serial Number340178“Case Back Signed: Seiko Time Corp. SEIKO Stainless Steel 4006-6027 Water Resistant 340178 Japan A”
Case Diameter39 mm“Cased in a robust 39mm cushion case, all in stainless steel.”
Jewel Count17 jewels“17 jewels, day/date indicator”
Reported DateApril 1973“dated from April 1973.”
Bracelet Capacity6 3/4 inches (17.2cm)“it will fit a wrist up to 6 3/4” (17.2cm).”

Visible details

  • Stainless steel cushion case with a blue outer bezel ring.
  • Dark dial with day-date display at 3 o'clock and an inner alarm ring.
  • Crown positioned near 3 o'clock with an alarm pusher button at 2 o'clock.

Research qualifications

  • The text gives contradictory caliber references, listing Cal. 4006A in the description and Cal. 4005A under movement notes.
  • Movement and case back are not directly depicted in the provided photos.

Photograph identity and source facts were screened before import; rights clearance remains pending.

Consulted source

Shop 1973 Seiko Bell-Matic Watch - 4006-6027 – SECOND HAND HOROLOGY

Reviewed 2026-10-21 · Record 8dd1d00ed6

Terms in this record

Glossary explanations for terms named in this object’s record.