Short answer
Ref. 5050 is the Blancpain Fifty Fathoms Grande Date. Blancpain lists a 45 mm case, a big date at 6 o'clock, and calibre 6918B with 120 hours of power reserve. Fakes of this reference exist, but they are rarer than fake Rolex Submariners. Most bad examples share three faults: a stock movement under a decorated rotor, a dial that copies the big date as a printed or glued part, and shallow caseback engraving.
What ref. 5050 is
The 5050 sits above the standard Fifty Fathoms Automatique in the line. The case is steel or titanium, 45 mm across, with a sapphire crystal and a screw-down crown. Water resistance is rated at 300 m. The bezel turns one way and carries a marked scale. Prices for a genuine example sit in the five-figure USD range on the secondary market, which is the main reason copies appear.
The big date
The genuine watch shows two date discs under one window at 6 o'clock. Both numerals sit on the same plane. There is no step, no shadow line, and no gap in the middle of the number. The font is thin and even. On a fake, the two digits sit at different heights, the font is heavier, and the date flips near midnight with a visible lag.
Movement
Calibre 6918B runs at 28,800 vph (4 Hz) and carries a silicon balance spring. A display back shows the bridges, the jewels, and the rotor. Fakes use a base movement from a third-party supplier. Tell-tale signs: plain, unmarked bridges, screws with damaged slots, a rotor with a printed logo instead of an engraved one, and a power reserve that dies in under 40 hours.
Caseback and numbers
The caseback holds a reference number and a serial number. The digits are cut deep and sit in a straight line. Laser engraving on fakes looks grey and flat under a loupe. Take a photo of the numbers and compare them with the movement number. Blancpain can confirm a serial against its records.
Checks before you buy
- Ask for a clear photo of the movement, not the dial.
- Ask for the case number and the movement number together in one shot.
- Check the date window at 11:55 p.m. and again at 12:05 a.m.
- Weigh the watch. Steel 5050 and titanium 5050 differ by several grams.
- Confirm the seller accepts a return after a watchmaker opens the case.
Red flags
- Price under USD 3,000 for a running example.
- No movement photo in the listing.
- Bezel insert that shows bubbles or a wavy edge.
- Box and papers sold as a set with no matching serial.
- Seller who refuses an inspection by a watchmaker.
What is not public
Blancpain does not publish production totals for the 5050. No reliable count of fakes exists. Treat any claim of exact numbers as unverified. Verification through the brand and a watchmaker remains the only firm test.