Now available at auction from Second Vintage
A quintessential 1960s Seiko day-date automatic, this sought-after Seikomatic Weekdater features a beautifully preserved silver sunburst dial and a distinctive full day display at six o'clock.
Brand: Seiko
Model: Seikomatic Weekdater
Reference Number: 6206-8990
Serial Number: 5533359
Movement: Automatic, caliber 6206A, 26 jewels
Dial: Silver sunburst with applied gold-tone indices and full day display
Case Size: 37mm (excluding the crown)
Case Material: Gold-tone, stainless steel caseback
Production Year: 1965
Condition: Good vintage condition. Movement serviced on 16 October 2026. Timegrapher: +15+18s/day, performing remarkably well.
Dial and Hands
The exceptionally clean and attractive vintage dial features a well-preserved silver sunburst finish. Applied gold-tone indices are clean, and the printed text remains crisp and fully legible, including the signature full day display positioned at six o'clock. Under high magnification, minor dust or microscopic spotting is visible. The original gold-tone dauphine hands show age-consistent oxidation and spotting on their surfaces, complementing the honest character of the watch.
Case and Crystal
The gold-tone case presents honest vintage wear, showing moderate scratches and handling marks throughout. Plating wear is visible on the lug edges and case flanks, as well as on the thin gold-tone bezel, which displays scratches consistent with the case. The stainless steel caseback, marked EGP for Electro Gold Plated, features crisp engravings and a beautifully preserved, distinctive dolphin motif. The small, knurled gold-tone crown is unsigned. A domed acrylic crystal protects the dial, remaining clear with some light surface scratches and scuffs.
Movement
Powered by the 26-jewel Seiko caliber 6206A automatic movement, the mechanism appears clean with bright gold-colored plates and rotor. There are no obvious signs of corrosion or damage, and the plates feature crisp engravings. Recording +15+18s/day on the timegrapher, it is exhibiting remarkable accuracy and consistency, performing brilliantly for a vintage timepiece. The movement was serviced on 16 October 2026.
Strap
The watch is paired with a black leather strap featuring an alligator pattern. The strap is in good condition and shows light wear.
Condition
Good vintage condition. The movement was serviced on 16 October 2026 and, supported by the recorded timegrapher result, is performing very strongly. The silver sunburst dial is excellently preserved, while the hands show expected oxidation. The gold-tone case displays moderate scratches and visible plating wear on the lugs and flanks, retaining a crisp stainless steel caseback with a clear dolphin motif. The domed acrylic crystal exhibits light surface scuffs.
Dimensions
The case measures 37mm in diameter (excluding the crown).
Remarks
This Seikomatic Weekdater offers a highly attractive silver sunburst dial and the classic full day display that defines the model. The preserved dolphin motif on the caseback and the strong mechanical performance make this a highly appealing example of mid-century Japanese watchmaking.
History
The Seiko Seikomatic Weekdater reference 6206-8990 was produced during the mid-1960s, a period when Seiko was rapidly advancing its automatic movement technology and refining its design language. Produced around 1964 and 1965, this model is powered by the caliber 6206A, a reliable 26-jewel automatic movement. The Weekdater series is a collector favourite, celebrated for its clean dial layout and the practical integration of a day and date complication. With its 37mm case diameter, 19mm lug width, and 44mm lug-to-lug distance, the reference 6206-8990 offers a substantial and elegant presence on the wrist.
Payment and Shipping
Payment must be completed within 1–3 days after purchase.
Your watch will be professionally and securely packaged, then shipped with tracking and insurance for your peace of mind.
We use fast express shipping, with typical delivery within 1–4 business days, depending on the destination.
Please note that vintage watches may show minor signs of wear, aging, or imperfections, which are considered normal for watches of this age.
We kindly ask you to review all photos carefully before bidding. We photograph each watch from multiple angles to provide the most accurate representation possible, and the photos form an important part of the description.
The timegrapher assessment if provided is seen as an indication of the movement’s condition under fully wound testing conditions. As with all vintage watches, results may vary in daily use.
If you have any concerns regarding functionality or defects after delivery, please contact us within 3 days of receiving the watch so we can assist you.
As with all used watches, water resistance is not guaranteed.
If you have any questions, feel free to contact us after the auction ends.
/ Second Vintage
SKU: SEI-MWJ-0005











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Seiko Seikomatic Weekdater 6206-8990 (1965)
Seiko • 1965
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