A. Lange & Söhne spent seven years developing the Zeitwerk before its 2009 launch. The premise was to build a wristwatch that displayed time in jumping digital format (the way a digital watch does) but using a fully mechanical movement, on a much larger and more legible scale than the few previous mechanical-jumping-hour pieces in horological history (Pallweber-style pocket watches from the late 19th century, the Audemars Piguet Star Wheel, the IWC Pallweber, etc.). Lange's solution was the "time bridge": a horizontal silver bridge spanning the dial, with three apertures showing the hours disc on the left, the tens-of-minutes disc in the middle, and the units-of-minutes disc on the right.
The mechanical challenge: every minute, the units-of-minutes disc jumps once. Every ten minutes, both the units and the tens jump simultaneously. Every hour, all three discs jump in perfect unison. This requires substantial energy delivered instantly, and the underlying movement needs to keep extremely consistent timekeeping rate despite the irregular torque loads. Lange's answer was Cal. L043.1, a hand-wound movement with a constant-force escapement (the remontoir) that decouples the discs from the main barrel and supplies energy in fixed pulses, so the rate stays constant whether the watch is fully wound or near the end of its 36-hour reserve, and whether it is between minute jumps or right after a triple-disc hour jump.
The launch references in 2009 were the platinum ref. 140.025, white-gold ref. 140.029, and pink-gold ref. 140.032. Subsequent variants extended the architecture into striking-time territory: the Zeitwerk Striking Time (2011, ref. 145.025) added a chiming hammer that strikes the hours and quarters; the Zeitwerk Decimal Strike (2017, ref. 143.050) chimes every ten minutes; the Zeitwerk Date (2019, ref. 148.030) added a peripheral red marker for the date around the dial. The Zeitwerk Honeygold "Lumen" (2019, 100-piece LE) used a semi-transparent sapphire dial with luminous numerals; the Zeitwerk Minute Repeater (2015, USD ~440,000) is the platform's grand complication.
The current Zeitwerk catalogue includes the Zeitwerk ref. 142 in white gold and pink gold, the Zeitwerk Date ref. 148, and various special editions. Retail for the standard Zeitwerk is approximately USD 105,000 in white gold, USD 130,000+ in pink gold, USD 195,000 in platinum. The watch has remained one of A. Lange & Söhne's most distinctive products, and the only modern jumping-hour mechanical wristwatch with a fully integrated three-disc digital display on this scale. The architecture has not been copied, and the constant-force escapement remains a Lange-specific solution.
