Answer: a fake Datograph is a copy of the A. Lange & Söhne Datograph, a manual-wind chronograph made in Glashütte, Germany. Copies fail on four checks: movement type, outsize date, case thickness, and weight. Any watch with a rotor behind the sapphire back is not a Datograph.

Datograph Basics

A. Lange & Söhne released the Datograph in 1999. The first reference was 403.035 in platinum. The movement, caliber L951.1, is manual-wind. It uses a column wheel, a flyback function, and a jumping minute counter. Later models include the Datograph Perpetual (2006), the Datograph Up/Down (2012), and the Datograph Perpetual Tourbillon (2016). Case size runs about 39 mm to 41 mm, by reference.

Movement Checks

Turn the watch over. The real Datograph has no rotor. It is hand-wound. Copies sold as a Datograph often hide a self-winding movement with a decorative rotor, or a Seagull ST19 hand-wind chronograph.

Look at the finish. Lange uses a three-quarter plate in untreated German silver, screwed gold chatons, and blued screws. The balance cock carries freehand engraving. A copy shows laser engraving with shallow lines, or no engraving at all.

Check the minute counter. The real counter jumps one full minute at a time. A copy drags.

Dial and Date Checks

The outsize date sits at 12 o'clock. It uses two separate discs. On a copy the two digits sit at different heights, or the aperture is printed on the dial. The date on the real watch changes with a jump. Copies roll.

Lange uses applied gold markers. Copies use glued or printed markers. Dial text should read A. Lange & Söhne, Glashütte i/SA, and Made in Germany. Watch for a missing umlaut on Söhne, or the spelling Glashutte or Lange & Sohne.

Case and Weight Checks

Genuine Datograph cases come in platinum, rose gold, white gold, and steel on a small number of special editions. Platinum is dense. A platinum Datograph on a strap weighs about 120 g to 140 g. Copies use steel or brass under gold plate and feel light.

Measure the case. Copies run thicker than the real watch. A case height of 14 mm or 15 mm points to a copy. The Datograph Up/Down measures about 12.8 mm tall.

Check the caseback and lugs. Real casebacks are sapphire with a laser-etched reference and case number. Those numbers must match the movement number and the papers.

Price and Paperwork

Genuine Datograph watches sell for tens of thousands of dollars. A new platinum Datograph lists above $100,000. Listings at $300 to $2,000 are copies. A box, papers, and a service record from A. Lange & Söhne support authenticity. Lange keeps production records and can verify a serial number.

Legal Note

In the United States, trafficking in counterfeit goods with a counterfeit mark is a federal crime under 18 U.S.C. § 2320. US Customs and Border Protection seizes counterfeit watches at import.