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The Encyclopedia of Horology

Pocket watch · Open-face pocket watch

1930s Seikosha Pocket Watch

Partially verified

This open-face pocket watch by Seikosha is estimated by the source to date to the 1930s. It features a 50 mm SKS case fitted with a mineral glass crystal. The cream-toned dial displays black Arabic numerals alongside an inner chapter ring of red 24-hour indicators and a subsidiary seconds register positioned at 6 o'clock. The watch is powered by an unjeweled manual-wind Seikosha movement noted for an unusual keyless works design. According to the seller, the timepiece was serviced in January 2023.

Dial and case front of the Seikosha open-face pocket watch
Dial and case front of the Seikosha open-face pocket watch — TokeiMedic. Rights pending — permission not yet requested. Original source

Catalogue identity

Source
tokeimedic.com
Category
Pocket watch · Open-face pocket watch
Maker / attribution
Seikosha
Reference
Not recorded
Catalogue / lot identifier
S0944
Source-reported date
circa 1930s
Source-reported place
Japan
Source-reported serial
15389

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

Dial and Case Configuration

The timepiece presents an open-face metallic housing specified by the seller as an 'SKS' case measuring 50 mm, fitted with a mineral glass crystal. A pendant winding crown and attached bow are situated at the 12 o'clock position on the case perimeter.

The light-colored dial features prominent black Arabic hour numerals, encircled internally by an inner track printed in red indicating 13 through 24 hours. The dial is signed 'SEIKOSHA' below 12 o'clock and has blued steel hands including a spade-tipped hour hand. At 6 o'clock, a subsidiary seconds register features black markers and a red '18'.

Evidence for this section
  • “Case SKS”
  • “Case size 50mm”
  • “Crystal mineral glass”
  • “Winding crown and bow positioned at 12 o'clock on a metallic open-face case.”
  • “Light-colored dial with prominent black Arabic hour numerals and an inner 13-24 hour track printed in red.”
  • “Subsidiary seconds register at 6 o'clock featuring black markers and a red '18'.”

Reported Movement and Mechanical Design

The listing notes a manual movement with caliber listed as 'Seikosha', leaving the jewel entry empty in the specification table while discussing an unjeweled layout in the description.

The seller describes an unfamiliar keyless works design that became displaced upon removing the wheel train bridge during disassembly, preventing photographic documentation of that mechanism. The seller also reports a service completed on January 10, 2023, noting wear and tear on parts without rust.

Evidence for this section
  • “Movement Manual”
  • “Caliber Seikosha”
  • “He told me that this movement design and lack of jewels points to watch being made before the war, most likely in 30's, with exact year unknown.”
  • “It has very "interesting", to put it lightly, keyless works design that I have never seen before.”
  • “Movement is clean, no rust, but there is wear and tear on parts.”
  • “Service Jan 10, 2023”

Dating and Documentation Limitations

Attribution to the 1930s relies on informal oral communication rather than archival records. The seller recounts asking a local watchmaker who suggested that the movement design and lack of jewels pointed to pre-war production, 'most likely in 30's, with exact year unknown.'

Individual tracking identifiers in the listing comprise SKU S0944 and serial number 15389. The exact placement of the serial number is not specified in the text, and internal movement views are not documented in the source images.

Evidence for this section
  • “I spoke with a local, old watchmaker, in his 70's. He told me that this movement design and lack of jewels points to watch being made before the war, most likely in 30's, with exact year unknown.”
  • “SKU# S0944”
  • “Serial # 15389”

Open research questions

  • What specific caliber model corresponds to this manual unjeweled Seikosha movement?
  • Where is serial number 15389 engraved (movement plate, inner case back, or exterior case), and does Seikosha ledger data clarify its manufacturing year?
  • What is the historical or functional significance of the red '18' marking on the subsidiary seconds dial?

Source evidence

Recorded claims and source quotations for 1930s Seikosha Pocket Watch
FieldSource-reported valueSource quotation
SKUS0944“SKU# S0944”
Serial Number15389“Serial # 15389”
Case Size50mm“Case size 50mm”
CaseSKS“Case SKS”
CrystalMineral glass“Crystal mineral glass”
Service DateJan 10, 2023“Service Jan 10, 2023”
CaliberSeikosha“Caliber Seikosha”

Visible details

  • Light-colored dial with prominent black Arabic hour numerals and an inner 13-24 hour track printed in red.
  • Subsidiary seconds register at 6 o'clock featuring black markers and a red '18'.
  • Blued steel hands including a spade-tipped hour hand.
  • Winding crown and bow positioned at 12 o'clock on a metallic open-face case.
  • Dial signed 'SEIKOSHA' below the 12 o'clock position.

Research qualifications

  • Dating to the 1930s relies on seller communication with a local watchmaker rather than factory archival records.
  • Internal movement and case back details are described by the source but are not visible in the primary photograph.

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

Consulted source

1930's Seikosha Pocket Watch – TokeiMedic

Reviewed 2026-10-21 · Record 59317d82d4

Terms in this record

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

Other open-face pocket watch records