Short answer
A fake Datograph is any A. Lange & Söhne Datograph that did not come from the Glashütte manufacture. The genuine watch is a hand-wound flyback chronograph with a column wheel movement, a jumping minute counter, and an outsize date. Copies hide a mass-produced chronograph behind a decorated plate. The difference shows in case thickness, the date discs, the pusher feel, and the finish of the engraving.
What the genuine Datograph is
A. Lange & Söhne released the Datograph in 1999, and it reset expectations for the modern chronograph. The catalog lists it as a hand-wound flyback chronograph with an outsize date and a jumping minute counter. Series production cases come in platinum, pink gold, white gold, and Honeygold. Lange does not build an automatic Datograph, and it does not list a steel Datograph in the standard lineup. Any seller who claims otherwise is describing something other than a factory watch.
Movement tells
Turn the watch over. The Datograph has a sapphire caseback, and a hand-wound movement fills it, with a three-quarter plate, Glashütte ribbing, gold chatons, blued screws, and a hand-engraved balance cock. The engraving is cut by hand, so it shows slight changes in depth and spacing from one watch to the next. Laser engraving looks flat and uniform under a loupe.
If you see a rotor, the movement is automatic and the watch is not a Datograph. If you see a flat plate with stamped decoration and a small exposed balance, the movement is a base chronograph with an ornamental cover. Both are common shortcuts in copies.
Dial, case, and date tells
Start with the outsize date. On the real watch, two separate discs sit side by side and align on the same plane. They snap over at midnight and stay level with the dial. On copies, the date is often one printed disc or two discs at different heights, and the numbers sit crooked or shadowed.
Next, look at the subdials. The chronograph minute counter should jump one step at a time, not sweep. Pushers on the real watch have a short, firm travel. Loose or mushy pushers point to a base movement. Case thickness is another marker. Real Datograph cases run about 13 mm thick. Copies often add 1 to 3 mm to fit a thicker movement and a spacer ring.
What you need
- Digital calipers
- A 10x loupe
- A kitchen or postal scale for the watch head
- Reference photos of the exact generation you are viewing
- Papers, service records, or a seller who permits inspection
How to check a Datograph in hand
- Measure the case with calipers across the 4 and 10 o'clock points, then record diameter and thickness.
- Weigh the watch head with the strap removed. Precious metal reads heavier than steel or plated brass at the same size.
- Turn the watch over and confirm there is no rotor and that the balance cock carries hand engraving.
- Set the date and watch the two discs move. They must land level and aligned.
- Run the chronograph through start, stop, and reset, then watch the minute counter for a jump instead of a sweep.
- Check the reference and serial numbers against the papers and the caseback engraving.
- Take the watch to an authorized service center for a movement inspection before you pay.
Price and paperwork tells
Ask what the seller paid and where the watch was serviced. A full service on a Datograph runs into four figures, and owners keep the receipts. A price far under market for the metal and generation is the oldest sign of a copy. Missing papers, a re-stamped caseback, and a seller who avoids a service center check all point the same way.
Legal note
U.S. Customs and Border Protection treats counterfeit watches as prohibited merchandise. Importing one can lead to seizure and destruction, and selling one as genuine is fraud. Buy from a seller who allows an inspection period and a written return policy.