【Product Description】 The Seiko 5 Actus SS (Ref. 6106‑8670) is a sporty yet refined automatic watch that captures the confident design language of mid‑1970s Japanese watchmaking. Its slim tonneau‑shaped stainless‑steel case around 36–37 mm across, combined with a sunburst dial, applied indexes, and sharp baton hands, creates a versatile aesthetic that works equally well in business and casual settings while remaining distinctly vintage. With its clear minute track, contrasting hands, and practical day‑date display at 3 o’clock, the watch offers excellent legibility, and the curved case with integrated lugs ensures comfortable everyday wear on the wrist. 【Historical and Collector Significance】 The 6106‑8670 embodies the 5 Actus SS philosophy, bringing Seiko’s “five key features” (automatic winding, day‑date display, shock resistance, water resistance, and practical case design) together with strong value for money. It is powered by the robust automatic caliber 6106C, a 21,600 bph movement with 23 jewels, hacking seconds, and a push‑to‑set quickset system that allows intuitive adjustment of the date and bilingual day at the crown. Produced in the 1970s, well‑preserved examples labeled “SS” and often marked “Made in Japan” are sought after by enthusiasts of Japanese vintage watches, appreciated for their reliable mechanics, clean sunburst dials, and wearable case proportions within the broader Seiko 5 Actus family. 【Specifications】 Brand: Seiko Model: SEIKO 5 ACTUS Reference number: 6106‑8670 Serial number: 534615 Movement: Automatic Day display: English and Japanese Case dimensions: approx. 37 mm (excluding crown) Bracelet material: Stainless steel 【Wrist Size Adjustment】 Adjustable from approximately 16.3 cm to 17.7 cm by adding or removing links and changing the micro‑adjustment holes on the buckle. Currently set at 17 cm (center position). 【Condition】 Case: There are some scratches and scuff marks, but no noticeable scratches or stains. (Please refer to the photos.) Bezel: There are some scratches and scuff marks, but no noticeable scratches or stains. (Please refer to the photos.) Dial: No noticeable scratches or stains are visible. (Please refer to the photos.) Crystal: No noticeable scratches or stains are visible. (Please refer to the photos.) Bracelet: There are minor scratches and scuff marks, but no noticeable scratches or significant stains. (Please refer to the photos.) 【Crown and Movement】 Time Setting: Pull the crown out to set the time. Date Quick Set: With the crown in the normal position, press it in lightly to advance the date by one day. Day & Date Quick Set: With the crown in the normal position, press it in firmly and deeply to advance both the day and date by one day simultaneously. (Please refer to the caliber specifications below for details.) The automatic winding mechanism is functioning normally. 【Accessories Included】 Watch only (no box or papers) 【Other Notes】 Made in Japan 【Shipping】 Ships via EMS or DHL international registered mail (with tracking and insurance). The estimated delivery time to Europe is approximately 7–14 business days after shipment.​ 【Calibre Specifications】 Movement: Seiko 6106 Automatic Calendar: English/Japanese bilingual day‑of‑the‑week + date display. Quick‑set method: Push‑in crown (push‑type quick‑set). Calendar Operation Specifications (movement changes based on push depth): Date Fast‑Forward: From the crown's “normal position,” a “shallow push” advances only the date by one day. Date + Day Fast‑Forward: From the normal position, a “deep, firm push” advances both the date and day simultaneously by one step (days cycle in English→Japanese→English order). Depending on the individual watch, behavior may vary, but this two‑stage push specification is typical for the 6106 series. Important Safety Precautions: Avoid push‑to‑advance operations between 9:00 PM and 2:00 AM, as the calendar switching mechanism is active and damage may occur. When adjusting the calendar, it is recommended to first set the time to approximately 6:00. When pushing the crown, hold the case firmly and press the crown straight down, avoiding force at an angle. Practical Setting Method (Steps for Actual Use): First set the time to around “6:00” to avoid damaging the calendar mechanism by staying outside the 9:00 PM–2:00 AM window. Set the date to the day before the target date with shallow pushes from the normal position. Use deep pushes from the normal position to advance both the date and day of the week step by step until they reach the correct position, stopping the day at either English or Japanese as preferred. Finally, pull out the crown and set the time to the current time, crossing midnight while keeping AM/PM in mind so that the date advances correctly and matches the intended day.