Short Answer

A fake Datograph Up/Down is a replica of the A. Lange & Söhne Datograph Up/Down, a hand-wound flyback chronograph with an outsize date and a power-reserve display that the brand introduced in 2012. Replicas come in two tiers: mechanical copies built on a decorated Chinese hand-wound chronograph movement, and budget automatic or quartz copies whose subdials do not function. The fastest test is simple. If the chronograph and the power-reserve indicator both work, you are looking at the upper tier. If either one is decorative, you are not.

What Up/Down Means

The German words AUF and AB sit on the dial next to a small scale. AUF means the mainspring is wound, AB means it is nearly run down. On the genuine watch this indicator tracks a 60-hour reserve. On a replica it is often a printed decal. Ask the seller for a short video that shows the hand moving as the watch is wound.

Prerequisites

  • Reference photos of the genuine watch for side-by-side comparison.
  • A caliper, or a seller willing to measure the case for you.
  • A video of the chronograph and power reserve running, not only still photos.

How to Evaluate One

  1. Ask for the case measurement. The genuine case is 41 mm across. Copies often run thicker to fit a bulkier movement.
  2. Request a photo of the movement through the caseback. Genuine watches show the L951.6 caliber with a hand-engraved balance cock and polished steel parts. Replicas show a plain or laser-etched plate.
  3. Watch a video of the chronograph start, stop, and reset. The pushers should give a firm click and the hands should snap back to zero.
  4. Test the flyback. The genuine watch restarts the chronograph with one pusher press while it is still running. Most replicas cannot do this.
  5. Check the outsize date. Both discs should sit on separate wheels and jump together at midnight. A single printed disc is a giveaway.
  6. Wind the crown and watch the power-reserve hand. It should climb toward AUF over several turns of the crown.
  7. Compare subdial positions and the AUF/AB scale against reference photos taken at the same angle.
  8. Inspect the crown and pushers for plating wear, and confirm the crown seats flush against the case.

Common Red Flags

  • Subdials that never move, or a power-reserve scale that is printed on the dial rather than driven by the movement.
  • Listings that use press photos of the genuine watch. Ask for a dated photo of the actual piece you will receive.
  • A visible quartz tick on the running seconds subdial.
  • A price far below the mechanical tier, which usually signals a quartz build.
  • Sellers who call the watch genuine or offer to ship it as a gift to dodge customs.

Legal Note

Replicas are counterfeit goods. Importing them into the United States is prohibited, and selling one as genuine is fraud. Buy and wear them as replicas, never as the real thing.