【Product Description】 The Seiko Ref. 6106-7580 is an automatic wristwatch from the 1970s, reflecting Seiko’s practical and contemporary design approach of the period. It features a stainless-steel case with a balanced, slightly tonneau-shaped profile paired with a sunburst dial, applied hour markers, and baton-style hands. A day-date display is positioned at 3 o’clock, and the dial layout is designed for clear legibility in daily use. The case proportions and integrated lugs provide a comfortable fit on the wrist while maintaining a distinctly vintage aesthetic typical of mid-1970s Seiko production. 【Historical and Collector Significance】 This model is powered by the Seiko 6106 automatic movement, typically configured with 23 jewels and operating at 21,600 vibrations per hour. The movement includes a hacking function and a push-type quickset mechanism for the day-date, consistent with its original specifications. Associated with the Seiko 5 Actus line, the 6106-7580 reflects the series focus on automatic operation, day-date functionality, durability, and practical case design aimed at everyday use. Examples retaining original components such as the dial, hands, and case are collected as representative pieces of mid-1970s Seiko production, appreciated for their reliable mechanics and period-correct styling among vintage Seiko enthusiasts. 【Brand】 Seiko 【Model】 Seiko 5 Actus 【Reference number】 6106-7580 【Movement】 Automatic (Seiko 6106) 【Day display】 English and Japanese 【Case dimensions】 Approx. 37 mm (excluding crown) 【Bracelet material】 Stainless steel 【Wrist size adjustment】 Adjustable from approximately 15.9 cm to 17.1 cm by adding or removing links and using the micro-adjustment holes on the buckle. Currently set at 16.5 cm (center position). 【Condition】 Case: Some scratches and minor wear, but no noticeable deep scratches or stains (see photos). Bezel: Some scratches and minor wear, but no noticeable deep scratches or stains (see photos). Dial: No noticeable scratches or stains (see photos). Crystal: No noticeable scratches or stains (see photos). Bracelet: Some scratches and minor wear, but no noticeable damage or major stains (see photos). 【Crown operation】 Time setting: Pull out the crown to set the time. Date quick-set: With the crown in its normal position, lightly push it in to advance the date by one day. Day and date quick-set: With the crown in its normal position, firmly push it in to advance both the day and date by one step. 【Movement condition】 The automatic winding mechanism is functioning correctly. 【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. 【Calendar specifications】 Movement: Seiko 6106 automatic. Display: English/Japanese bilingual day-of-the-week and date. Quick-set type: Push-in crown (two-stage push quick-set system). 【Calendar operation notes】 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 deeper, firm push advances both the date and day by one step (the day cycles in English → Japanese → English order). Behavior may vary slightly between individual watches, but this two-stage push specification is typical for the 6106 series. 【Important precautions】 Avoid performing push-to-advance operations between 9:00 PM and 2:00 AM, when the calendar switching mechanism is active, as this may cause damage to the gears. When adjusting the calendar, it is recommended to first set the time to around 6:00 to avoid the switching period. When pushing the crown, hold the case firmly and press the crown straight in, avoiding angled force. 【Practical setting guide】 Set the time to around 6:00 before starting calendar adjustment. With a shallow push from the normal crown position, advance the date to the day before the target date. Use deep pushes from the normal position to advance both the date and day step by step until they match the current day and date, stopping at the preferred language (English or Japanese). Pull out the crown and set the current time, passing midnight once to ensure the calendar changes correctly to the final intended date.