The A. Lange & Söhne 1815 Rattrapante Perpetual Calendar is one of the hardest watches to fake well. Its split-seconds chronograph adds a second chronograph hand, a rattrapante clamp, and a second column wheel to a perpetual calendar. Most replicas copy the look and skip the mechanism. To tell a fake 1815 Rattrapante from the real thing, run the split-seconds function first. If the second hand does not stop and restart on command, the watch is not a true rattrapante, and the rest of the inspection matters less.

What the Genuine Watch Does

A. Lange & Söhne introduced the 1815 Rattrapante Perpetual Calendar in 2013 in a 41.9 mm case, first in platinum with gold versions later. Inside sits the hand-wound caliber L101.1, a split-seconds chronograph with two column wheels, a rattrapante clamp, and a perpetual calendar with moon phase. The pusher at 2 o'clock starts and stops the chronograph. The pusher at 4 o'clock resets it. The pusher at 10 o'clock controls the split hand.

How to Inspect a Suspected Fake

  1. Start the chronograph with the pusher at 2 o'clock and let both hands sweep together.
  2. Press the pusher at 10 o'clock and watch the lower hand stop while the upper hand keeps running.
  3. Press the 10 o'clock pusher again and confirm the stopped hand snaps back to catch the running hand with no jump and no lag.
  4. Reset the chronograph with the pusher at 4 o'clock and check that both hands fly back to 12 and sit exactly on top of each other.
  5. Advance the date and moon phase, then check that the correctors respond without grinding.
  6. Turn the watch over and look for a hand-engraved balance cock, screwed gold chatons, and a Glashütte three-quarter plate in untreated German silver.
  7. Measure the case with calipers and confirm 41.9 mm across, then weigh it. Platinum and gold versions feel dense in the hand.
  8. Read the dial under a loupe: the A. Lange & Söhne signature, the Arabic numerals, and the railway minute track should be crisp and level.

Red Flags

  • The 10 o'clock pusher does nothing, or it stops the whole watch.
  • The split hand drifts and never lands exactly on the running hand.
  • The movement is a decorated ETA or Seagull base with a rotor behind a display back.
  • The pushers feel soft or stick halfway instead of clicking.
  • The case back shows machine engraving instead of freehand engraving.

What Replicas Cannot Reproduce

Even a high-end replica of the 1815 Rattrapante Perpetual Calendar cannot deliver a real rattrapante mechanism. A true split-seconds works through a clamp and an isolator that let one chronograph wheel stop while the other keeps turning. Copying that in a hand-wound movement takes hundreds of parts and a second column wheel. A replica maker can add a third pusher that moves a decorative hand, and it can print the correct functions on the dial. Both tricks fail the moment the buyer presses the split pusher. Judge a replica on honest limits: a working chronograph, a clean dial, an accurate case diameter, and a movement that matches what the case back shows.