The Zenith A6621 was introduced on the occasion of Zenith's centenary in 1965 and was produced until about 1969. The design may surprise today's watch collectors, but it was very popular back then. The bi-color dial features three silver-colored sections that appear lighter or darker depending on the viewing angle. The stainless steel case consists of a wide beveled bezel, which has a date display under a loupe at 6 o'clock. This creates the shape of a keyhole, which is why the cool nickname has become popular among vintage collectors, recently serviced…
Case:
o UFO-style stainless steel case, serial 621A101, profissional polished
o Fine condition with strong geometry
o 35mm without crown / 38mm lug to lug / 10.5mm thickness / 18mm lug width
o Plexiglass with minor scratch and marks, specifically in the magnifying glass in the date window area.
o Generic crown - Important Note regarding the Original Crown: The watch has recently undergone a full mechanical service and is currently fitted with a functional replacement crown for daily operation. The highly sought-after original Zenith star-signed crown is included in the sale as an uninstalled spare part. During the service, it was noted that a fragment of the previous stem remains lodged inside the original crown's thread. To strictly preserve the integrity of this rare original part and avoid any risk of cosmetic or structural damage through aggressive extraction methods, the watchmaker opted to leave it untouched. It is delivered alongside the watch, allowing the future owner to decide whether to undergo specialized micro-extraction (such as an alum bath solution) to reuse it.
Movement:
o Mechanical Automatic cal. Cal 2542 PC - serviced by watchmaker in May 2026
(movement was disassembled, washed, lubricated) - photo of timegrapher
Dial:
o flawless two-tone dial - date window under a magnifying glass at 6 o'clock - signed "SWISS MADE
Bracelet Material:
o New 18mm in dark blue leather, with generic steel buckle
Conclusion:
This Zenith 'Keyhole' A6621 is a masterclass in 1970s Swiss watch design, combining a robust manufacture movement with an unmistakable retro-futuristic aesthetic. Ready to wear and accurate after its recent overhaul, it represents a fantastic opportunity for serious Zenith collectors to acquire an authentic piece of space-age horological history.
please see photos as they are part of the description.
No box or papers, no water proof test, sold as is, any question feel free for ask...
Keep in mind that it is a vintage watch, it is normal to be 1/2 minute early or late
wrist-treasure
