ith the 1815 Rattrapante Perpetual Calendar, A. Lange & Söhne presents three of the most sophisticated watchmaking complications in a classic design. The equally rare and ambitious combination of a split-seconds or rattrapante chronograph with a perpetual calendar now appears in a new guise, featuring an 18-carat white gold case with a pink-gold dial. The new 1815 Rattrapante Perpetual Calendar is limited to 100 pieces.

Perpetual Calendar marked a milestone in A. Lange & Söhne’s more recent history: no less than seven chronograph calibres had previously been crafted by the Saxon manufactory. Equipped with a specially developed movement, it united three of the most elaborate complications – very rare in this configuration – while maintaining the classic, elegant design of the 1815 watch family. The outstanding timepiece excels in the thanks to its eponymous complications, the 1815 Rattrapante Perpetual Calendar sets standards in both short-time measurement and the display of calendar periods.

The rattrapante function of the 1815 Rattrapante Perpetual Calendar represents one of the greatest horological challenges. In addition to the conventional functions of a chronograph, this sophisticated complication is capable of measuring intermediate times and comparative times as well as determining minimum and maximum values in the course of one minute. Since the balance wheel of the manufacture calibre L101.1 beats with six semi-oscillations per second, the stopped times can be recorded with an accuracy of one sixth of a second. High-precision readings are assured thanks to the additional graduation on the peripheral minute scale.

The precisely orchestrated proceedings within the movement can be observed through the sapphire-crystal caseback. The classic two-column wheel transmission is used to control the measurement of stopped and intermediate times. As is typical for A. Lange & Söhne, technical intricacy is coupled with a high degree of artisanship. The upper surfaces of all moving parts are decorated with straight graining while the peripheral chamfers are polished. Only an experienced finisseur has the skill to polish the bevels to sharp and flat perfection.

While the rattrapante chronograph is capable of measuring different time intervals to a fraction of a second, the remarkable technical feat of the perpetual calendar lies in its “long-term memory”. As its name suggests, the complex and prescient mechanism ensures that the date, day of the week and month are correctly displayed ‒ every single day, during decades, even taking leap years into account. The calendar indications must only be corrected by one day but not until 1 March 2100; according to the rules of the Gregorian calendar, the leap year will then be skipped.

The high-precision moon-phase display has also been programmed with the long term in mind. It so closely emulates the duration of the synodic orbit of the earth’s satellite that it would take 122.6 years for the display to be corrected by one day.

Not only the technical data but also the well-organised arrangement of its displays. Following the Datograph Perpetual Tourbillon (2019) and the Lange 1 Perpetual Calendar (2021), it is the third A. Lange & Söhne timepiece showcasing an 18-carat pink gold dial: the warm, golden hue contrasts elegantly with the cool white gold of the case. With a traditional railway-track minute scale, Arabic numerals and the harmonious arrangement of the four subsidiary dials, the dial embodies the essence of the watch family named after the birth year of Ferdinand Adolph Lange.

The manifold displays of the perpetual calendar and the rattrapante chronograph echo the classic aesthetics of earlier Lange pocket watches. The two pairs of combined calendar indications are arranged at 3 and 9 o’clock. The left subsidiary dial shows the date and day of the week, the right the month and leap year. Sharing an auxiliary dial with the subsidiary seconds at 6 o’clock, the moon-phase display provides an expressive colourful accent. The minute counter and power-reserve indicator are located at 12 o’clock. The shorter gold hand in the inner circle reveals when it is time to deliver new power to the movement via the winding crown. The longer hand made of blued steel imparts information about the stopped minutes.

Incorporating traditional design and engineering features, the manually wound movement L101.1 totals an impressive number of 631 individual parts. The mechanism of the perpetual mechanism. A screw balance, which is driven by the balance spring developed and manufactured in-house, ensures high rate stability. Lange-typical quality hallmarks such as screwed gold chatons, blued screws, an elaborate whiplash precision index adjuster and the hand-engraved balance cock are visible through the sapphire-crystal caseback. The finissage of the movement, which is assembled twice, reflects A. Lange & Söhne’s high standards in every single detail.

The dimensions of the new 1815 Rattrapante Perpetual Calendar remain unchanged: the case boasts a diameter of 41.9 millimetres and a height of 14.7 millimetres. In addition to the new 1815 Rattrapante Perpetual Calendar in white gold with a pink-gold dial limited to 100 pieces, the model also comes in a platinum/argenté and pink-gold/argenté case-dial combination.

TECHNICAL SPECIFICATIONS

MOVEMENT

Lange manufacture calibre L101.1, manually wound, crafted to the most exacting Lange quality standards, decorated and assembled by hand; precision-adjusted in five positions; plates and bridges made of untreated German silver; balance cock engraved by hand

No. of movement parts 631

No. of jewels 43

No. of screwed gold chatons 4

Escapement Lever escapement

Oscillator Shock-resistant screw balance, superior-quality balance spring manufactured in-house, frequency of 21,600 semi-oscillations per hour, precision beat adjustment mechanism with lateral setscrew and whiplash spring

Power reserve 42 hours when fully wound

FUNCTIONS

Time indicated in hours, minutes and subsidiary seconds dial with stop seconds; rattrapante chronograph with minute counter; perpetual calendar with date, day of week, month, moon phase and leap year; power-reserve indicator

OPERATING ELEMENTS

Crown for winding the watch and setting the time; two chronograph buttons, one button to operate the rattrapante mechanism; separate recessed correctors for advancing the date, day of week, month and moon phase

Case dimensions Diameter: 41.9 millimetres; height: 14.7 millimetres

Movement dimensions Diameter: 32.6 millimetres; height: 9.1 millimetres

MATERIALS

Crystal and transparent caseback
Sapphire crystal (Mohs hardness 9)

Case
18-carat white gold

Dial
Solid pink gold

Hands and appliqués
Rhodiumed gold; blued steel hour, minute, minute counter and rattrapante hand, rhodiumed steel chronograph hand

Strap
Hand-stitched alligator leather, dark brown

Buckle
Deployant buckle in 18-carat white gold

Limited edition 100 watches, edition number engraving, boutique-exclusive