Catalogue record · Pocket watch
Seikosha Interwar and Wartime Pocket Watch
Needs researchThe generation of Seikosha pocket watches that followed the pioneering Laurel line, produced as Japan's own watch industry expanded through the interwar years and into wartime production.
Overview
Following the Laurel line that established Seikosha's own pocket-watch manufacture in the early twentieth century, K. Hattori & Co.'s Seikosha works expanded its pocket-watch production through the interwar period and into the Second World War, supplying both domestic civilian and military markets.
This record covers the general later run of Seikosha keyless lever pocket watches distinct from the earlier, specifically documented Laurel-era origin line, including plainer wartime-utility grades produced under material and labour constraints of the period.
History
Japan's watch industry grew substantially through the interwar decades as Seikosha's manufacturing capability matured beyond its initial Laurel-era foundation, and the firm supplied timepieces for both civilian and military use through the Second World War.
Wartime production in Japan, as in other combatant countries, generally favoured plainer, more utilitarian finishing and case materials than peacetime commercial grades, reflecting material shortages and production priorities of the period.
Design
Movement architecture continues the Swiss-pattern lever convention established in the earlier Laurel-era production, with detail changes reflecting the manufacturing firm's developing capability over this period.
Military-issue examples, where identifiable, generally show plainer finishing and case construction consistent with wartime utility production rather than a peacetime commercial grade.
Movement
As with the earlier Laurel-era line, published Swiss- or American-style serial dating references do not apply directly; specialist Japanese-language sources give the most reliable dating for specific calibres and periods.
Case
Base metal and chrome-plated wartime-utility cases wear and corrode more readily than silver or better-plated peacetime cases, and this should be described honestly rather than treated as damage requiring aggressive restoration.
Any military issue stamps or unit markings, where present and legible, are useful evidence for a specific example's service history and should be conserved rather than polished away.
Dial and hands
Dial legibility conventions for military and utility examples tend toward plain, bold Arabic numerals, distinct from more decorative domestic commercial-grade dials of the same general period.
Technical specifications
| Movement | Seikosha keyless lever movement, later interwar and wartime calibres |
|---|---|
| Movement type | Keyless lever movement |
| Escapement | Swiss-pattern lever escapement |
| Jewels | Varies by grade; military-issue and export examples were generally plainer than the finest domestic-market grades |
| Winding and setting | Keyless stem-wind, stem-set |
| Size | Standard pocket-watch sizing |
| Power reserve | Approximately 30–36 hours |
| Frequency | 18,000 vibrations per hour (2.5 Hz), typical of Swiss-pattern lever movements |
| Accuracy | Ordinary commercial-grade accuracy for utility and military-issue examples; better domestic grades were more carefully finished |
| Complications | Running seconds in most examples |
| Escapement | Swiss-pattern lever |
| Winding | Keyless stem-wind, stem-set |
| Manufacturer | Seikosha (K. Hattori & Co.) |
| Period | 1920s–mid-1940s |
Identification
- Movement or dial marked Seikosha; military issue marks, where present, should be checked against specialist references on Japanese wartime military timepieces rather than assumed from appearance alone.
- Distinguishing this later generation from the earlier, specifically documented Laurel-era line requires attention to model and calibre markings rather than the Seikosha name alone.
Variations
- Civilian commercial grades and military-issue utility grades both occur within this period, differing substantially in finishing and case material.
Serial numbers and dating
- As with the earlier Laurel-era line, comprehensive published serial-number references comparable to major Swiss or American makers are less widely available in English-language sources; specialist Japanese-language references should be consulted for precise dating.
Known examples and institutional holdings
- Held in the manufacturer's own successor company archive and in museum collections documenting the Japanese watch industry's wartime and interwar production.
Collecting
- Of interest both to collectors of the Seiko lineage and to those specifically collecting Japanese military-issue timepieces; the two collecting interests should not be conflated without confirming a genuine military provenance.
- No prices are given here.
Restoration and conservation
- Standard lever-movement servicing considerations apply; a watchmaker unfamiliar with this period's Japanese parts should confirm compatibility before undertaking repair.
- Movement work — cleaning, lubrication, mainspring replacement, pivot or jewel work — belongs with a qualified watchmaker. Conserve original parts; do not refinish dials or polish cases to remove honest wear.
Bibliography
- Manufacturer historical archive material (consult current editions).
- Histories of the Japanese watch and clock industry, including its wartime production.
Bibliographic entries are given only at the level we can support. Where an edition, publisher or ISBN is not confirmed, it is deliberately omitted rather than invented.
Related photographs
No confidently matched photograph of this subject has been found yet. These photographs show a closely related record, and are not examples of the type described on this page.
Sources & references
- Manufacturer archive and museum publications.
- Historical studies of Japanese wartime and interwar watch manufacturing.
Where sources disagree, the disagreement is stated rather than resolved silently.