Seiko Seikomatic Weekdater 4001355 (1964)

Now available at auction from Second Vintage A classic 1960s Seiko day-date automatic, this Seikomatic Weekdater is defined by its signature dial layout, featuring the full day of the week prominently displayed at the 6 o'clock position. The well-preserved silver sunburst dial and distinctive recessed crown at 4 o'clock make it a compelling representative of Seiko's mid-century design language. Brand: Seiko Model: Seikomatic Weekdater Serial Number: 4001355 Movement: Automatic, 26 Jewels Dial: Silver sunburst with applied indices and full day display Case Size: 37 mm (excluding the crown) Case Material: Gold-tone Production Year: 1964 Condition: Good vintage condition. Movement serviced on 16 October 2026. Timegrapher: +15+20s/day, performing remarkably well. Dial and Hands The silver sunburst finish is well preserved, providing a clean and highly legible backdrop. Applied indices and text are crisp, complementing the classic Seikomatic Weekdater layout which features a full day display in English at the 6 o'clock position. While minor dust or very light spotting is visible under macro inspection, the dial remains overall very clean. The gold-tone dauphine hands retain an original appearance with light age-related wear, showing some minor oxidation and spotting visible under close inspection. Case and Crystal The 37 mm gold-tone case features a distinctive recessed crown at 4 o'clock, alongside an integrated style bezel. The case is heavily worn, characterized by significant plating loss on the lugs that reveals the underlying base metal. Scratches and scuffs are present throughout the case flanks and bezel area, and the caseback shows significant wear to the outer engravings. The recessed crown shows some wear. The domed acrylic crystal exhibits light surface scratches and scuffs visible at certain angles, with no major cracks or chips. Movement Powering the watch is an automatic movement featuring 26 jewels. The gold-colored movement plates and rotor are engraved with "SEIKO" and "26 JEWELS". The caliber appears generally clean with no obvious severe corrosion, though there are some light marks on the rotor. The timegrapher records a rate of +15+20s/day. Exhibiting remarkable accuracy and consistency, performing brilliantly for a vintage timepiece. The movement was serviced on 16 October 2026. Strap The watch is fitted with a black leather strap featuring a crocodile pattern. The strap shows light wear and creasing. Condition Good vintage condition. The movement was serviced on 16 October 2026 and, supported by the recorded timegrapher result, is performing very strongly. The well-preserved silver sunburst dial remains clean and highly legible, showing only very light spotting under macro. The gold-tone case is heavily worn, demonstrating significant plating loss on the lugs that reveals the base metal, alongside scratches across the flanks and bezel. The caseback engravings also exhibit significant wear, and the domed acrylic crystal bears light surface scratches. The movement is clean and operational. Dimensions The case measures 37 mm (excluding the crown). Remarks A classic 1960s Seiko day-date automatic, this Seikomatic Weekdater stands out through its signature full day display at 6 o'clock and the practical recessed 4 o'clock crown. The beautifully preserved silver sunburst dial offers a striking contrast to the heavily worn character of the case, making it an appealing choice for collectors of early automatic Seiko models. History Introduced in the early 1960s, the Seikomatic Weekdater line represented an important evolution in Seiko's automatic day-date offerings. Known for its distinct layout featuring the full day of the week prominently displayed at the 6 o'clock position, the Weekdater was aimed at professionals seeking both elegance and practicality. The recessed crown at 4 o'clock was a deliberate design choice, emphasizing the efficiency of the automatic winding system by suggesting manual winding was rarely necessary. Today, these models remain appreciated by vintage Seiko enthusiasts for their mid-century charm and reliable mechanical architecture. 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-MDJ-0009