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The Encyclopedia of Horology

Tokyo, Japan

Seikosha

Partially verified

Clocks and watches

History

The Hattori factory from which Seiko developed, initially making wall clocks.

Major innovations

    Known markings

    • 'Seikosha'

    Serial numbers

    This archive holds no verified serial-number table for this maker. Do not date a piece from its serial number alone; use case hallmarks, movement construction, trade directories and documented comparison examples.

    Collecting significance

    Originality of dial, hands, case and movement is the main consideration. Confirm that the movement belongs to the case and that the dial has not been refinished, and record what is verified separately from what is inferred.

    Diagram

    escape wheelpallets and leveroscillator
    Schematic: escapement arrangement. An outline schematic drawn to show the arrangement of the parts discussed here. It is not a dimensioned working drawing and does not depict a particular maker's calibre.

    Sources & references

    1. Kathleen H. Pritchard, Swiss Timepiece Makers 1775–1975
    2. Brian Loomes, Watchmakers and Clockmakers of the World
    3. Mikrolisk trademark and maker index
    4. Published trade directories and period material catalogues

    Where sources disagree, the disagreement is stated rather than resolved silently.