Short answer

A fake Patek Philippe 1518 is a counterfeit watch built to look like a reference Patek Philippe made from 1941 to 1954. No copy is exact. The real 1518 holds one mechanical movement, caliber 13-130 Q, that drives a chronograph and a perpetual calendar. Most fakes hold a stock chronograph movement with calendar discs that never move on their own. Real 1518s sell at auction for six figures and up. Fakes sell for a few hundred dollars.

What reference 1518 is

  • Built 1941 to 1954. The first serially produced perpetual calendar chronograph wristwatch.
  • Production: 281 pieces, based on auction house counts.
  • Cases: yellow gold, rose gold, stainless steel. Four steel pieces are known.
  • Case size: 35 mm. Solid case back. Hand wound.
  • Movement: caliber 13-130 Q, a Valjoux 23 base with a perpetual calendar module. Column wheel, horizontal clutch.
  • Dial: two calendar apertures at 12, a moon phase window, a 30-minute chronograph register, and a printed scale on the dial edge.

How fakes differ

  • Display case back. The real 1518 has a solid back. A see-through back on an "1518" is a hard sign.
  • Calendar discs that do not advance. On fakes the month, leap year, and moon phase are printed or set by hand. The moon phase is a 24-hour day/night plate.
  • Size. Fakes run 38 mm to 42 mm. The real case is 35 mm.
  • Movement. Fakes use a Seagull ST19, an ETA 7750 copy, or quartz. The real caliber is hand wound, 13 lignes, with a column wheel.
  • Metal. Plated steel instead of gold. A gold original weighs far more than a plated copy.
  • Price. A "new" 1518 offered under $2,000 is a counterfeit.

Checks that hold up

  1. Read the case number and the movement number. Both are stamped on the real watch, and both sit in Patek Philippe records.
  2. Weigh the watch and measure the case. 35 mm, and the mass that fits the metal.
  3. Set the watch and watch the calendar change at midnight. Real perpetual calendars move the month, date, and moon phase without help.
  4. Ask for the Extract from the Archives from Patek Philippe, or a service invoice from Patek. Ask the archive service about scope, since terms have changed over time.
  5. Send the watch to a Patek Philippe service center or an independent specialist. No seller paperwork replaces this step.

Market and legal notes

Phillips sold a stainless steel 1518 in Geneva in November 2016 for CHF 11,002,000. Gold examples trade in the low six figures to over $1 million.

US law treats counterfeits as contraband. 18 U.S.C. 2320 covers trafficking in counterfeit goods, with prison terms up to 10 years for a first offense. Customs and Border Protection seizes counterfeit watches at ports of entry. A buyer who resells a counterfeit can face civil claims from the brand owner.