The first and strongest check on a fake IW323727 is the case back. The reference string, the case number, and the quality of the engraving together give away more clone builds than any other single step, because that mark is the hardest part of the watch to reproduce at low cost. The sections below rank the checks in the order that returns the most information for the least risk, and each one lists what it catches, what it misses, and the buying situation where it earns its place.
1. Case Back Engraving and the Reference String
IWC marks the case back with the reference number, a case number that belongs to that one watch, and the Swiss Made label. On a real watch the digits sit in a clean line, with even spacing throughout the string and a depth that stays constant across the whole mark. Clone engraving tends to drift: the spacing opens up in the middle, the digits thin out at the edges, and the font does not match case backs from the same production period.
What it catches
- Wrong digit shapes, with the 3 and the 2 usually the first to look off
- Shallow laser marks where the real case uses a deeper engraved or stamped impression
- Case numbers that repeat across listings, or that fail to match the papers and the movement
What it misses
- The best clone cases, where the back is copied from a real watch and reproduced well
- Mixed builds that pair a real case back with a clone case
- Polished or refinished case backs where the original mark has been buffed soft
Use it when: you are looking at listing photos or standing at a table with a loupe. It costs nothing, and it filters out most listings before you spend money on anything else.
2. Movement, Caliber, and Winding Feel
Ask for a clear photo of the movement with the back off, or have a watchmaker open the watch in front of you. The caliber engraved on the rotor and the bridges should match the caliber IWC lists for that reference in its own archive. Most clone builds start with a third party movement, then add decorative plates, blued screws, and a rotor carrying an IWC style engraving.
What it catches
- Jewel counts and bridge shapes that belong to a common third party movement rather than an IWC caliber
- Engraving that stops where the eye stops, with plain metal underneath the visible layer
- Winding that feels gritty or stiff, and a rotor that rattles when the watch tilts
What it misses
- Service replacements, where a real watch carries a non original but correct-spec part
- Clones fitted with a genuine movement pulled from a damaged watch
- Anything you cannot see without opening the case
Use it when: the seller has paperwork, a return window, or a watchmaker nearby. This is the check that separates a good case back from a good watch.
3. Dial, Date Wheel, and Hand Finishing
Dial work is where small budgets show. Look at the applied markers under a loupe: real ones sit flat, catch light on a crisp bevel, and carry lume that fills the frame without touching the edges. Check the date window for a font that matches the rest of the dial, a wheel that sits level behind the aperture, and a jump that lands dead center at midnight.
What it catches
- Printed markers that sit too thick or too flat compared with applied metal
- Date fonts with the wrong weight, or a wheel that sits off center in the window
- Hands with rough edges, uneven lume, or a seconds hand that does not reach the track
What it misses
- High end clone dials made from the same printing process as the original
- Redials and aftermarket dials fitted to a genuine watch
- Watches photographed in soft light where surface detail disappears
Use it when: the photos are sharp enough to zoom. If they are not, ask for a straight-on dial shot at an angle, because flat lighting hides everything this check depends on.
4. Case, Bracelet, and Crown
Run a finger along the line where brushed and polished surfaces meet. On a real watch that transition is sharp and deliberate, with no rounding and no polishing dust left in the gap. Check the end links: they should sit flush against the case with no gap and no wobble. Then check the clasp engraving, the crown threading, and the crown seal, since those parts are usually the last place a clone build spends money.
What it catches
- Soft or rounded case edges where a machine polished the whole case in one pass
- End links with visible gaps or a bracelet that rattles against the lugs
- Crowns that thread roughly, or a crown that sits proud of the case line
What it misses
- Well finished clone cases, which now match the original on surface work
- Genuine watches that have been polished hard by an earlier owner
- Weight differences you cannot feel while the watch is on a display stand
Use it when: you can handle the watch in person. Bracelet feel and crown action are the two things that photographs cannot fake.
5. Papers, Price, and Seller Behavior
Full set means box, booklet, warranty card or digital record, and a serial that ties everything to the same watch. Match the case number on the back to the card. Make sure the reference on the card reads the same as the reference on the case. Then compare the asking price against current listings for that reference on the secondary market, and treat any large gap as a question rather than a bargain.
What it catches
- Stock photos reused across several listings, and sellers who will not send new shots
- Cards with a model name, a reference, or a case number that does not match the watch
- Sellers who refuse a meeting at a watchmaker, or who push for a fast wire transfer
What it misses
- Genuine watches sold without papers, which is common and not by itself a problem
- Fake paperwork paired with a fake watch, which can look complete and consistent
Use it when: you are weighing two similar offers. Paperwork does not make a watch real, but a seller who cannot produce it and will not allow an inspection is telling you something useful.
A Sequence That Works in Practice
- Read the case back and confirm the reference string, the case number, and the engraving quality.
- Ask for a movement photo or an inspection by a watchmaker.
- Zoom on the dial, the date window, and the hand finishing.
- Handle the watch if you can, and judge the bracelet, the crown, and the case edges.
- Match the paperwork to the case number, then compare the price to real listings.
Two notes before you buy. First, a check that passes does not prove authenticity; a check that fails almost always proves the opposite, so stop at the first hard failure. Second, buying or selling counterfeit goods is illegal in the United States, and shipments of fake watches are seized at the border. That does not change how you inspect a watch, but it does change what you should do with one after you decide it is a clone: report it, return it if you have a route, and do not pass it on.