The Zenith Keyhole, or Schlüsselloch, was designed to celebrate the company’s centenary.  Model reference 621A.


The model code tells us that this is post 1963, but Zenith watches are very tricky to date perfectly.  However in the excellent Zenith book by Manfred Rossler they state that the Keyhole was designed for the 100th anniversary, so circa 1965 will be quite accurate.


Making a watch that is both different but also legible and not too wild is not easy – the basic design of 99% of watches would be recogisable to someone from 100 years ago.  The clever people at Zenith did add their twist with the date position at 6 and a cut out in the wide bezel to read the date.  Technically this required no clever adjustments to the movement, which would take time and money to develop.  The movement is a 23 jewel automatic, Zenith calibre 2542PC, which is running well.  The watch is very original – many have either lost the NSA bracelet, or had had the dial repainted and have lost the pattern that extends from the calendar and adds to the keyhole look.  The dial on this does have patina but is original.  The bracelet clasp and the crown are also signed originals, but the clasp does have a pair on N letters engraved on it.  The bracelet is quite short and our sister website,, may have extra links if required.  The bracelet has been cleaned in our ultrasonic bath.  A leather strap could be fitted if preferred.

This watch will be supplied with our branded presentation box and our Certificate of Authenticity.

This watch has been checked against the Watch Register and has not been reported as lost, stolen or implicated in fraud, and a copy of that certificate will also be included.

Please see the HD video for more detail.  All photos and videos are part of the description and are of the actual watch unless mentioned.  We do not photoshop any pictures, and the images are copyright of and should not be used without permission.


Width with crown  36.1 mm

Width without crown  35.0 mm

Between lugs  18 mm

Lug to lug length  37.9 mm

Case Thickness  10.4 mm

Bracelet will fit a maximum wrist size of 180 mm.  The bracelet can be sized for you if you give us your wrist size when placing the order.

All sizes are approximate.  The watch is photographed on a wrist of 190mm/7.5 inches without the clasp being clipped together.

Included with this watch is a 3 month guarantee and free delivery to UK addresses.  If you live outside the UK we can still deliver to most countries.  Please see our Worldwide Shipping information, or Contact Us.   Payment can be made by most credit or debit cards, bank transfer or PayPal.

From 1st September 2021 we will be planting a tree for every watch we sell, working with the International Tree Foundation (Est 1922) to make this business positive on carbon.  By buying anything pre owned you are effectively reusing what already exists, but this takes it further and makes us feel good.