A Documented 1948 Product
Birse-Clock / Birse-Clock-Court J.B. was associated with Court Watch Co. SA. The Birse-Clock mark was registered in 1944, and by 1948 a small clock based on Birse movements was advertised in Swiss chess circles under the sales-facing name 'Grob's Schachuhr.'
Tournament Use
The earliest documented use is the International Christmas Chess Tournament in Lucerne in 1948. The model's best-known early appearance came at the Dubrovnik Olympiad in 1950, placing it squarely within elite postwar international chess.
Compact Swiss Construction
The advertisement described a sturdy wooden case measuring about 14.5 × 8 × 4 cm, solid alarm-clock movements, an hour signal, winding indicators, and a one-year guarantee. The movements are described as four-jewel Swiss mechanisms.
Historical Significance
Birse did not reinvent chess timing. Its contribution was to apply Swiss small-movement precision and compact construction to a trusted tournament format.