Answer first: the fastest way to catch a fake Blancpain Villeret 6654 is to test the calendar works and then look for the correctors under the lugs, not on the side of the case. A genuine 6654 is a complete calendar watch with day and month in twin apertures at 12 o'clock, a moonphase at 6 o'clock, and a blued serpentine date hand reading an outer numeral track. Counterfeits match that layout on the dial and fail behind it. I rank the checks below by how hard they are to fake, how little equipment they need, and how safe they are to perform on a watch you do not own yet.

What the Villeret 6654 actually is

The reference sits in Blancpain's Villeret line as the Quantième Complet, driven by calibre 6654, an automatic with a long power reserve and a silicon balance spring in current production. Most references measure around 40 mm and come in steel or gold. Because reference numbers, dial colors, and movement updates change over the years, pull the exact reference from the maker's own product page and compare against that, not against a forum photo of a different variant.

Forgers target this model because the dial is busy. Apertures, a moon disc, and a date track give plenty of places to hide sloppy work, and most buyers never handle a real one.

Check 1: Calendar function and the moonphase

Set the watch to a known date and leave it running. A real complete calendar advances day, date, and month on separate schedules, and the moon disc steps forward one lunar day at a time. Fakes show day and month windows that flip together, a moonphase that is a printed sticker, or a plain day and night disc painted to suggest a moon.

• Pro: needs no tools beyond a corrector, and no seller can hide a mechanism that does not move.
• Con: some fakes use a cheap donor calendar module, so the calendar works while the finish and feel still give the watch away.

Best for: remote deals where you only have video and a seller willing to set the watch on camera.

Check 2: The serpentine date hand and dial printing

Under a loupe, the genuine date hand is heat blued steel with a sharp taper and a clean edge. Genuine printing holds a crisp border and even ink density. Fakes show fuzzy numerals, a flat anodized hand, and date numerals that drift off the radial line. Aperture frames should be polished metal set level with the dial, not stamped foil.

• Pro: works from photos if the seller sends macro shots of the dial at 6 o'clock and the outer track.
• Con: high-end fakes print well, so this check narrows suspicion rather than settling it.

Best for: screening listings before you spend time talking to a seller.

Check 3: Correctors under the lugs

Blancpain places the calendar correctors under the lugs, reached from the back with peg wood or the supplied tool. Fakes move them to the caseband, where you see four small pushers around the side, or they drop correctors and expect the crown to do the work. Turn the watch over and inspect between the lugs at the 2, 4, 8, and 10 positions.

• Pro: decisive, quick, and visible in a single caseback photo.
• Con: a handful of older or modified genuine cases vary, so confirm the layout for the exact reference first.

Best for: any in-person inspection, and the first thing to request in a photo set.

Check 4: Case, lugs, and caseback finishing

Run a fingernail along the lug bevels. Genuine cases carry a defined bevel, consistent brushing direction, and polished flanks with a mirror that does not ripple. Fakes show soft transitions, over-polished edges, and brush lines that change direction between surfaces. Check crown logo height and the depth of the caseback engraving, which is stamped on fakes and shallow.

• Pro: catches even fakes with a working calendar module.
• Con: a genuine watch that has been refinished can show the same soft edges.

Best for: hands-on viewing under daylight, where reflections read true.

Check 5: Movement and calibre markings

Calibre 6654 shows striped bridges, a signed rotor, and clean perlage on the base plate, with jewel settings in gold chatons on some versions. Counterfeits use mass-produced automatics with stamped bridges, a glued rotor medallion, and no fine regulation. Read the calibre engraving and the caseback reference, and compare both to the paperwork. A seller who refuses a movement photo has answered your question.

• Pro: the hardest area to counterfeit at a low price.
• Con: opening the case voids some warranties and risks damage, so let a watchmaker do it.

Best for: high-value purchases where you can arrange a pre-purchase inspection.

Check 6: Serial, papers, and service history

Match the caseback serial to the certificate and to any service invoice from an authorized center. Reference numbers should agree with the dial configuration and case metal. Boxes and papers are easy to fake, so treat documents as a secondary signal and the watch itself as the primary evidence.

• Pro: a service record from an authorized center is strong corroboration.
• Con: paperwork alone proves nothing, and clean fakes ship with convincing sets.

Best for: confirming a watch you have already inspected in person.

The check I would trust most

If you can run only one test, test the calendar and then look under the lugs for the correctors. Those two together separate a real Villeret 6654 from nearly every counterfeit built to imitate it, because both require the forger to reproduce the movement and the case architecture rather than the appearance. Work in this order: verify the exact reference, ask for macro dial shots, ask for a caseback and under-lug photo, request a movement photo, then arrange an inspection by a watchmaker before money changes hands.