Short answer
A fake Tourbograph 510.105 is a counterfeit watch sold under the name of the A. Lange & Söhne Tourbograph. No workshop makes a faithful version of it. The genuine piece pairs a fusée-and-chain drive with a tourbillon, a rattrapante chronograph and a perpetual calendar, and its movement is assembled and finished by hand in Glashütte. Counterfeit sellers skip every one of those systems. What arrives is a generic automatic movement inside a decorative case, with a dial that copies the look from three feet away and nothing beyond that.
What the reference number means
Lange reference numbers identify a specific case metal, dial variant and production run. A seller who quotes 510.105 in a listing but shows a different number on the caseback, or shows no number, has already answered your question. Genuine engraving is cut into the metal and sits beside a matching movement number. Printed stickers, laser etching on a smooth blank, or a caseback with no number at all are grounds to walk away.
Why a real copy does not exist
- Part count. A Lange tourbillon chronograph movement runs into the high hundreds of components. Cloning it costs more than the counterfeit trade can recover on volume.
- Finishing. Anglage, black polishing and hand-engraved balance cocks are bench work, not line work.
- Complications. A working rattrapante and a perpetual calendar that tracks leap years are two separate engineering problems stacked in one case.
- Materials. Lange case alloys such as Honeygold are not sold to counterfeit workshops.
- Dial work. Applied numerals, engine-turned subdials and multi-layer lacquer are produced to a tolerance that cheap tooling does not hold.
How to identify a fake Tourbograph 510.105
- Request a macro photo of the dial and hands before you discuss anything else.
- Compare the caseback engraving to the reference number printed in the listing.
- Count the subdials and check whether the layout matches a perpetual calendar with a rattrapante counter.
- Ask for a video of the chronograph starting, stopping and returning to zero under power.
- Check the crown and pushers for the correct number, spacing and position.
- Weigh the watch and measure the case diameter with calipers.
- Have an independent watchmaker open the caseback and read the movement signature.
- Ask the seller for the service history and the original paperwork, then verify the numbers against the maker.
What you actually receive
Most listings that use this keyword ship one of two things: a quartz watch with a printed dial, or a low-grade automatic in a plated case. Both are made in the same factories that produce generic fashion watches. Neither has a tourbillon cage that rotates, a chain drive, or a calendar that advances on February 29. The giveaway is functional, not visual. Set the date to February 28 and watch what happens the next day. On a genuine perpetual calendar it jumps to March 1 in a non-leap year. On a counterfeit it goes to February 29 or stops.
Legal and practical note
Trafficking in counterfeit goods is a federal offense in the United States under 18 U.S.C. 2320, and customs officers seize shipments at the border. Buyers lose the money and the watch. If your goal is the look of a Lange tourbillon, a documented pre-owned piece from an authorized dealer or a reputable auction house is the only route that holds value and survives resale scrutiny.