Short answer
Fake 1815 watches copy the A. Lange & Söhne 1815, a hand-wound dress watch line released in 1995. Most fakes pair a stock Swiss or Chinese movement with a gold-plated case. The differences show up in the movement finish, the balance cock engraving, the case metal and the records that come with the watch. A genuine 1815 sells for tens of thousands of USD. A fake sells for hundreds.
The genuine 1815 in numbers
A. Lange & Söhne named the line after the birth year of Ferdinand Adolph Lange, 1815. The brand relaunched in October 1994 and added the 1815 in 1995. Cases come in yellow gold, rose gold, white gold or platinum. Sizes run 36 mm on early references, 38.5 mm on current three-hand models and 40 mm on the 1815 Chronograph. Movements are hand-wound and built in Glashütte. Reference 233.026 uses calibre L051.1 at 21,600 A/h. The 1815 Up/Down uses L051.2. The 1815 Chronograph uses L951.5. Jewel counts and dimensions differ across references.
Where fakes fail
- Movement finish. Genuine Lange calibres carry Glashütte ribbing on a three-quarter plate, screwed gold chatons, blued steel screws and a balance cock engraved by hand with a floral pattern. Fakes show laser-cut lines, plated chatons that are not gold, and engraving with repeating strokes.
- Case metal. Gold and platinum cases carry hallmarks and a 750 or 950 stamp. Plated brass and steel cases carry no such stamp, or carry a stamp that does not match the metal.
- Weight. Platinum runs about 21 g/cm3, 18k gold about 15.5 g/cm3, steel about 7.8 g/cm3. A plated fake feels light for its size.
- Numbers. The movement number is engraved on the movement and recorded by the manufacture. The case number is stamped in the caseback. Both must match those records.
- Price. A gold 1815 trades in the tens of thousands of USD. Listings at a few hundred dollars are fakes.
- Dial and hands. Real dials use printed Arabic numerals, a railroad minute track and heat-blued steel hands with polished bevels.
Steps to verify a used 1815
- Ask for the box, papers and service records. Lange records service work by movement number.
- Check stamps. Look for gold hallmarks and the case number in the caseback.
- Compare the movement number on the bridge with the number on the caseback.
- Photograph the balance cock with a macro lens or a loupe. Hand engraving has irregular cut depth.
- Send the movement and case numbers to A. Lange & Söhne or an authorized service partner. The brand does not run a public serial lookup.
- Have a watchmaker open the caseback and measure the movement. Lange calibres are in-house shapes, not stock ebauches.
Limits of a photo check
Phone photos cannot settle finish quality. Some fakes use a genuine case with a swapped movement, and some use a genuine movement in a recased body. Those need a watchmaker and the manufacturer records. If the numbers do not match, the watch is not a complete original.