Circa 1964 Seiko Cal 840 Seikomatic Slimdate 840 SUWA Gold-filled 30J Mechanical Watch

Make: Seiko
Type: Mechanical
Model: Seikomatic Slimdate
Year of Production: Circa 1964
Movement: 840
BPH: 18,000
Number of Jewels: 30
Hand and Dial: 3D 14K Solid-Gold Baton Indices and Dauphine Hands, and 14K 70 Micron Gold-Filled Case
Width: 36mm
Lug to Lug Height: 44mm
Thickness: 10mm
Lug Width: 18mm
Strap: Brand-New Hi-Quality Aviation Bund Genuine Leather Strap with Padding and Gold Buckle
Pouch / Box: Brand-New EVA Type Zipper Pouch

The Seiko 840 movement replaced the 830 (AKA 8301) movement and was later renamed the 8305. The 840/8305 debuted in February 1964 until 1972.

For Seiko Collectors and Vintage fans, this is a Pre-SUWA (logo) 30J Automatic in excellent condition. The Cool Spinner Logo below the 12H marker and 6 pointed star located below the "Diashock" wordings authenticates it's "AD" status i.e. solid gold markers and hands and 14K 70 micron gold-filled case; thus, this is a highly sort-after timepiece.

The 70 micron 14K gold-filled case, 14K solid gold hands and indices (for its age) are in excellent condition and had undergone a painstaking cleaning process and almost all imperfections have been meticulously removed. There may be a few minor scratches and age marks remaining but are almost invisible to the naked eye. It's original ivory white dial has Patina (Wabi-Sabi: The Perfect Imperfections / The Imperfect Perfections) growing at the dial edges and have moved inland at certain points. The crystal has been given a good rub and is almost spotless as well.

This watch is meant for the diehard Patina Dial lover.

The crown is original and is located at the 4H position and is nicely tucked away to prevent damage or snags. The date quickset works flawlessly by pulling out the crown to the first level to adjust the date via clockwise or counterclockwise (very unique!). The time is adjusted by pulling the crown out to the second level.

The movement was carefully stripped and meticulously cleaned via ultrasonic immersion, oiled, re-assembled and calibrated in September 2022. It should be able to operate unhindered for the next 5 to 10 years at the very least thereby providing the owner peace of mind.

Equipped with the 840 movement, it has an impressive 30 Jewels that operate at 18,000 beats per hour (BPH) giving it excellent accuracy and longevity. The time-grapher, after calibration shows excellent readings i.e. rate of +1 seconds every 24 hours and amplitude of 225. Such readings are excellent even by brand new modern automatic watch standards whereby the accepted tolerance is -20 to +40 seconds a day! This is a testament to the quality, excellent power reserve and longevity for such a vintage timepiece, the meticulous care provided over the years, and of course the painstaking expert calibration.

To the best of our knowledge and expertise when overhauling the timepiece, the watch is 100% original Seiko components from this particular watch. No parts were replaced with aftermarket parts or modified thereby it is considered in excellent condition.

Due to its age, this timepiece has not been water-resistant tested.

The case width and height are approximately 36m (without crown) and 44mm respectively. The lug width is 18mm and the genuine leather saddle strap can accommodate wrists up to 21.0cm; hence suitable for men and the modern women.

The watch comes with a vintage expendable gold plated bracelet and an additional brand new Crazy Horse Distressed Designed Saddle Brown leather strap with gold buckle as part of the deal. The Buyer is provided the option to choose a different design and coloured strap from my array of straps should he / she wishes to do so.

The pictures provided show the watch’s case in very good condition, and the movement within squeaky clean and well maintained. It has also been demagnetised to improve parts reliability, minimise wear & tear, and improve accuracy. The only drawback is the lack of documentation and original box. A nice purposeful carrying case or box will be provided instead.

Bear in mind that this watch has seen many of the previous owners’ ups and downs in life, and should be cherished and well taken care of for the next generation to savour such engineering beauty.

Yes, there are many other same / similar models in the market, BUT none has beautifully aged and as well maintained as what you see here. Hence, it is a no-brainer that this one-of-a-kind watch will make an extremely beautiful birthday present for that special someone. Another no-brainer is the fact that the value of this watch will appreciate over time.

Do also bear in mind that it will cost between S$ 180.00 to S$ 200.00 for an overhaul, an estimated S$ 80.00 to calibrate, and S$ 40.00 to buff such a watch case - these costs do not apply when purchasing this timepiece. So, if anyone was to sell such a timepiece at a low price yet claim that it has been serviced, one has to ask what kind of servicing was conducted, if any.

This is a highly sort-after Seiko Seikomatic Slimdate 840 14K Gold Filled 70 micron watch with a classy gold plated expendable vintage bracelet and Crazy Horse vintage designed leather strap that compliments the case and patina dial perfectly, and simply too hard to resists if you're a vintage patina nutty; so, be unique and wear something that is almost impossible to source.

This is a must-have for the Seiko die-hard fan, and in fact, any serious watch collector!


Seiko Cal 840 circa 1964 Seikomatic Slimdate SUWA Gold-filled 30J Mechanical Wrist Watch Timepiece