From Thiel to the DDR Industrial System
Gebrüder Thiel was founded in 1862 and, after the Second World War, became part of the Soviet-controlled Awtowelo system. The Ruhla production base then continued inside the industrial structure of the German Democratic Republic.
This institutional background distinguishes Ruhla from small specialist makers. The chess clock emerged inside a large, centralized manufacturing system capable of sustaining a product line over decades and exporting it internationally.
Friedrich Schildt and the First Ruhla Chess Clock
Friedrich Schildt, chief designer at Ruhla and an active chess player, developed the first clock around two modified Model 6 alarm-clock movements. The alarm mechanisms were removed, and a rocking lever linked the two movements so that one ran while the other was stopped.
The first 150 clocks were supplied for the 1951 World Festival in Berlin. The original Calibre 6 form remained in production from 1951 to 1954. The surviving record gives dimensions of 170 by 55 millimeters with a height of 90 millimeters, a polished wooden case, and a sliding rear cover.
Inside the Mechanical Interlock
The surviving documentation provides unusually detailed internal documentation of the Ruhla mechanism. The stop action used adjustable spring-wire pins to block the balance of the stopped movement. This is a precise mechanical explanation of how two ordinary clock mechanisms became one alternating chess timer.
The first version had internal winding and hand-setting. A 1954 redesign moved these controls outside the case, making routine use more convenient. The clock's visual indicators also evolved: the flag moved from near nine o'clock toward eleven for better lift and visibility, while the later 1961 version placed the red running indicator at three o'clock.
These changes are small individually, but together they show a mature design being refined through actual production experience.
A Documented Design Sequence
The Ruhla line is unusually useful because the surviving documentation provides a clear sequence. The first 150 clocks appeared in 1951, followed by the original Calibre 6 production from 1951 to 1954. The 1954 Model 69 redesign introduced a new case and external winding and hand-setting. In 1961, the Calibre 69/67 form arrived and the Gardé trademark was registered on April 19 of that year.
This was not one clock frozen in time. It was a continuing design family in which movement, case, controls, and visual indicators changed while the basic paired-movement architecture remained stable.
The Mature Gardé Form
The 1961 Calibre 69/67 version became the long-running mature architecture. It used a redesigned wooden case and Calibre 69/67 alarm-clock movements. The surviving record gives dimensions of 220 by 53 millimeters, a height of 120 millimeters, a screwed rear cover, external winding and hand-setting, and approximately 36 hours of running time.
Gardé became the export identity of the line. The Schildt study summarized in the surviving record states that most production was exported worldwide through a Portuguese distributor under the GARDE name.
Later Gardé clocks remained visible in high-level play, including Karpov–Kasparov, connecting the East German factory line to the highest levels of late mechanical-era chess.
A Remarkably Long Production Life
The surviving record states that Ruhla production continued through the end of clock production in 1989 and gives 1993 as the endpoint for Gardé. The distinction suggests that the production program and the brand's commercial life did not necessarily end at precisely the same moment.
The line therefore spans almost the entire postwar mechanical era. It began as Schildt's specific 1951 solution and grew into a standardized state manufacturing and export program.
Historical Significance
Ruhla/Gardé represents centralized scale. Unlike Posingis, where workshop production solved a local accessibility problem, Ruhla shows how a state industrial system could take a practical design, refine it across generations, and distribute it widely for decades.
It is also one of the best clocks for explaining how a mechanical chess clock actually works because surviving documentation preserves both external forms and internal construction across multiple generations.
For the website, this page should therefore connect directly to the Special Topic article on mechanical interlocks and switching systems.