Since the inaugural collection of the new era was showcased in the autumn of 1994, the exclusive timepieces with the attribute "Pour le Mérite" have represented the technological avantgarde at A. Lange & Söhne. Each of the four models launched so far is endowed with a fusée-and-chain mechanism. The RICHARD LANGE "Pour le Mérite", first introduced in 2009, exemplifies an ambitious tribute to precision in its purest form: the sole objective of its complication, discernible only on the movement side, is to improve rate accuracy. The pink-gold and platinum versions, now sold out, are now being complemented with a limited white-gold edition featuring a black dial.

The solid white-gold case of the new edition has a diameter of 40.5 millimetres. White Roman numerals and the rhodiumed gold hands contrast well against the black silver dial. Small Arabic numerals in red for 15, 30, 45, and 60 minutes add handsome nuances of colour to the underlying black-and-white design. A hand-stitched black alligator leather strap with solid white-gold buckle underscores the stylistic clarity of the RICHARD LANGE "Pour le Mérite".

Utmost technical complexity

The salient technical hallmark of the RICHARD LANGE "Pour le Mérite" – and of all "Pour le Mérite" models since 1994 – is a fusée-and-chain transmission that consummately defined new benchmarks in precision watchmaking. Inspired by historic pocket watches and integrated into a wristwatch by A. Lange & Söhne for the first time, the mechanism guarantees constant torque and thus stability of the amplitude of the balance across the entire power-reserve range. Wrapped around the mainspring barrel, the chain delivers the power of the mainspring to the wheel train via the cone-shaped fusée. This keeps the torque constant. When the watch is fully wound, the chain pulls at the smaller circumference of the fusée, i.e. at the shorter lever. Conversely, when the tension of the mainspring is nearly depleted, the chain pulls at the larger circumference of the fusée, the longer lever. In principle, the mechanism works like the gearing of a bicycle except that the gear ratios are infinitely variable rather than fixed.

The 636-part chain can support a weight of over two kilograms. But to fully exploit the positive effect of the fusée-and-chain device, the product developers added a technical refinement: two separate mechanisms block the winding system before fully wound and fully unwound states. Both prevent the chain – which is only 0.25 millimetres thick and 156 millimetres long – from being overstressed.

The fusée-and-chain transmission causes the fusée to rotate in one direction during the winding process and in the opposite direction when the watch is running. For this reason, it is necessary to ensure that the watch continues to run even when it is being wound. An elaborate planetary gearing inside the fusée maintains the flow of power from the fusée to the movement during the winding phase. It is composed of 38 tiny parts which the watchmaker must fit into the tight 8.6-millimetre inside diameter of the fusée.

All this remains concealed beneath the black dial. But the most important parts of the fusée-and-chain device are clearly visible through the sapphire-crystal caseback. Generously dimensioned openings in the three-quarter plate made of German silver reveal the mechanism.

Perfection down to the last detail

In the heart of the manufacture calibre L044.1, crafted to the strictest Lange quality criteria and lavishly decorated by hand, a freely oscillating Lange hairspring powers the large screw balance at a frequency of 21,600 semi-oscillations per hour. With four solid-gold poising screws, its moment of inertia can be adjusted precisely to the torque delivered by the fusée. The splendid finissage of all movement parts even includes straight graining of the upper side of the chain, which is also crafted in-house. Manifesting artisanship at its finest, the engravings on the balance cock as well as on the escape-wheel and fourth- wheel cock give each of the 218 watches the status of a unique work of art. The number of watches of this edition has a special meaning. The current number of global points of sale at which A. Lange & Söhne timepieces are available is 218.