Short answer
The 6654-3642-55B is a Blancpain Villeret Complete Calendar: a 40mm steel watch with day, date, month and a moon phase, driven by the in-house calibre 6654. Fakes of this reference are common. Most of them give themselves away in three places: the movement behind the sapphire back, the printing on the dial, and the calendar correctors on the case flank. If the asking price is a few hundred dollars instead of five figures, it is not a Blancpain, whatever the paperwork says.
What the real 6654-3642-55B is
The Villeret Complete Calendar is one of Blancpain's signature pieces, and the 6654 line has stayed close to the same formula for years. The details that matter when you are checking one:
- A 40mm case, slim for a complete calendar, with the stepped Villeret bezel and straight, beveled lugs.
- Day and month in twin apertures under 12, a blued serpentine hand for the date, and the moon phase at 6 o'clock.
- Self-winding calibre 6654 with a 72-hour power reserve, visible through a sapphire caseback.
- Finishing you can see with a loupe: Geneva stripes on the bridges, polished screw heads, an engraved rotor.
- Alligator strap on a pin or folding buckle, depending on how the watch was ordered.
One note on the number itself. Blancpain uses the middle group for the case and the last group for the strap setup, and dealers list the same reference with different dials and metals. That confusion is a useful signal, and I come back to it below.
Where a fake falls apart
The movement
Turn the watch over first. A counterfeit calendar watch is almost always a basic movement with a calendar module bolted on top, and it shows. Look at the rotor engraving, the shape of the bridges, the jewel count, and how the calendar parts sit on the dial side. The genuine calibre carries finishing that costs more than a fake watch sells for, and nobody bothers to replicate it.
The dial and the moon
Printing is harder to fake than people assume. Check the script signature, the weight of the Roman numerals, and the alignment of the apertures. The moon phase disc is a good test: on the genuine watch the moon is a shaped disc, not a flat printed shape. On many fakes the moon is stamped, and the stars around it sit at the wrong size or spacing.
The case and the correctors
Blancpain sets its calendar with recessed correctors that need a proper tool and sit flush with the case. Fakes often have protruding pins, holes drilled slightly off center, or a crown that feels gritty when you set the date. Run a fingernail along the lug bevels. On the real thing the transition is crisp and even. On a fake you feel a flat spot.
Price, papers, and lazy listings
Steel Villeret Complete Calendar watches trade in the five figures on the secondary market, so any example at a fraction of that is a counterfeit with a story attached. Photos are another tell. Plenty of fake listings use a stock image of a different metal or dial than the reference they name. Cross-check the number against the brand's own catalogue and against real dealer photography of the same reference.
Checklist before you hand over money
- Verify the reference number against official specs, including case metal and dial color.
- Ask for a photo of the movement through the caseback, then compare rotor engraving and bridge shapes.
- Study the dial printing at 10x magnification. Blurry edges, uneven spacing, or a flat moon are disqualifying.
- Confirm the correctors sit flush and need a tool.
- Weigh the price against real market data. A five-figure watch does not sell for four hundred dollars.
- Check that the seller accepts returns and that a watchmaker can inspect the watch before the sale closes.
A counterfeit also carries practical costs beyond the money. Blancpain will not service it, no auction house will sell it as a Blancpain, and US customs can seize it on import. Those are reasons to walk away even when the watch in the photo looks convincing.
Bottom line
The 6654-3642-55B is a complete calendar with a 40mm steel case, a blued date hand, a moon phase at 6, and the calibre 6654 under a sapphire back. Judge any example by the movement first, the dial second, and the price third. When all three line up, you have a real one. When one of them is off, you do not.