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

A BIRTHDAY WATCH IS A WATCH THAT WAS PRODUCED THE SAME MONTH AND YEAR AS YOUR BIRTH MONTH AND YEAR

Make: Seiko

Type: Mechanical

Model: Seikomatic Slimdate

Year of Production: March 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, 6 pointed star located below the "Diashock" wordings, it's "AD" status of solid gold markers and hands and 14K 70 micron gold-filled case makes this watch a highly sort-after timepiece.

The 70 micron 14K gold-filled case, 14K solid gold hands and indices 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. Its 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 was replaced with a brand new Japan made hi-quality new crystal.

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 as it should by uncorking the crown to the first and second level to adjust the date via clockwise or counter-clockwise (very unique!) and the hands respectively.

The movement was carefully stripped, meticulously cleaned, oiled, re-assembled and calibrated in 7 October 2025. It should be able to operate unhindered until the next servicing thereby providing the owner peace of mind.

Equipped with the 840 movement, it has 30 Jewels and operate at 18,000 BPH. The time-grapher shows excellent readings of 0 seconds and amplitude of 249 with a straight centred line! Such readings are exceptional 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 (w/o 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 brand new Crazy Horse Distressed Designed Saddle Brown leather strap with gold buckle as part of the deal.

The pictures provided shows the watch in stunning 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 March 1964 Seiko Seikomatic Slimdate 840 14K Gold Filled 70 micron watch 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 a watch that is extremely rare.

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