This year’s version of the Datograph Auf/Ab by A. Lange & Söhne, originally presented in platinum in 2012, has a pink gold case, 41 mm in diameter, 13.1 mm thick, and a black silver dial. The name Auf/Ab (Up/Down) refers to the power reserve indicator at the bottom of the dial, which points to Auf when the hand-wound watch has its entire reserve of 60 hours.
The watch has all the Lange characteristics: the very three-dimensional dial, with the tachymeter scale on a level slightly above the central part of the dial, the outsize date in its superbly detailed windows, the silver subdials providing contrast against the black dial, and the overall balance and symmetry.
The hands are differentiated in finish, pink gold with luminous coating for hour and minute hands, gold-plated steel chronograph hand with rhomboid counterbalance, and continuous seconds and minute-counter hands (each with a different design) in blued steel.
The L951.6 in-house calibre comprises 451 parts, running at 18,000 vph. and the sapphire caseback enables some components to be seen, including the column wheel, the three-quarter plate, the hand-engraved balance cock and four gold chatons. The refinements to the traditional chronograph pattern include the flyback function for instantaneous resetting, and a precise jumping chronograph minutes indication, so that the hand is always on the marker and never between two markers.
The Datograph Auf/Ab by A. Lange & Söhne has reference number 405.031