Seiko 5 Actus SS 6106-8440: Cushion Case, 25-Year Service Engraving (Fully Serviced)
A Seiko 5 Actus SS 6106-8440 is a Japan-market automatic from about 1969–1970: cushion steel case, day-date, hacking seconds. This one keeps the brushed finish in excellent condition. The caseback is hand-engraved for 25 years of service at Sugie Seiki, a precision metal-parts maker.
What the Actus SS name means
Actus sat above the ordinary Seiko 5. The “5” was Seiko’s own checklist: Diaflex mainspring, Diashock, automatic winding, day and date, water resistance. SS on the dial is Second Setting — pull the crown and the seconds hand stops, so the watch can be set to a time signal. Caliber 6106 is the automatic underneath: typically 23 jewels, 21,600 bph, Magic Lever winding, quick-set day and date by pushing the crown. The same 61-series idea later fed Seiko’s chronographs and the 61GS. On a 5 Actus it is a daily watch, not a dress flagship.
This Seiko 5 case
Reference 8440 is the cushion / tonneau Actus, about 40 mm across, 19 mm lugs, thick enough to read as a 1970s sports-dress watch and still clear a cuff. Brush on the top surfaces, polished flanks. On this example the brush is still even and the edges are still there. Excellent, not a later polish pretending to be original.
The unique history of Seiko 5 actus engraving
Japanese companies of this era gave a watch at a long-service mark. This caseback is hand-engraved for 25 years at Sugie Seiki. The lettering is cut by hand, not a printed sticker and not a modern laser job. It ties the watch to one workshop and one career. That is the reason this 8440 is not a generic Actus.
Specification
Maker: Seiko
Model: 5 Actus SS 6106-8440
Era: 1970 Feb
Case: Stainless cushion, brushed finish, excellent
Case Diameter: approx. 40 mm
Lug Width: 19 mm
Caseback: Hand-engraved, 25 years of service, Sugie Seiki
Movement: Automatic Caliber 6106, 21,600 bph, hacking, day-date
Dial: Actus SS, day and date at 3
A vintage Seiko 5 Actus SS 6106-8440 with the brush still on the cushion, and a named 25-year engraving on the back, is the Actus you buy for the case and the story together.
It comes with a Kyoto Series leather strap in any colour. Tell us which one.
