Enno Koopmann Bremen Chronometer Age Determination
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Background on Enno Koopmann, Bremen
- Location: Bremen, Germany
- Active: ca. 1890 – 1940
- Occupation: Watchmaker, dealer and precision mechanic; usually had watch movements supplied by Swiss manufacturers (e.g. BA Schild, FHF, or Unitas) and assembled/tested them in Bremen.
- Signatures: mostly “Enno Koopmann – Bremen” on the dial or movement engraving.
- Often specializing in high-quality table, marine or observation clocks
Serial numbers and typical time ranges
Since Koopmann was not a watchmaking manufactory in its own right, the serial number often comes from the manufacturer of the movement blank (ébauche), not from Koopmann itself. Nevertheless, certain time periods can be estimated, for example, by comparing known Swiss series.
| Serial number (approximately) | Estimated timeframe | Features |
|---|---|---|
| < 100,000 | before 1900 | Early lever escapements, silver cases, enamel dials |
| 100,000 – 300,000 | 1900–1915 | Rebberg or A. Schild/Unitas caliber, 15 rubies |
| 300,000 – 600,000 | 1915–1925 | Precision pocket watches, often with the inscription "Chronometer" |
| 600,000 – 1,000,000 | 1925–1935 | Late pocket watches, steel or nickel cases |
| > 1,000,000 | after 1935 | Late production models, possibly observation watches (military) |
Characteristic features of each decade
| Time | Features |
|---|---|
| 1890–1905 | Enamel leaf, Roman numerals, gold or silver case |
| 1905–1915 | Small wristwatches, 15 jewels, "Swiss Made" engraving |
| 1915–1925 | Precision pocket watches, often bought by officers (World War I) |
| 1925–1935 | Steel case, Arabic numerals, hands with luminous material |
| 1935–1940 | Observation watches and ship chronometer imports |
Koopmann, Enno
German watchmaker
Enno Julius Koopmann was born on May 13, 1880, in Brake. From 1904 to 1905 , he completed an apprenticeship at the German Watchmaking School in Glashütte . On July 7 , 1905 , he received his master craftsman's certificate. He was recognized as a chronometer maker and began conducting chronometer tests in 1908. He resided at Hafenstraße 148/150 in Bremen from 1905 until mid-August 1944.
His son Hans Koopmann continued the business of his father Enno Koopmann.
