Cal. 4S36, made from 2007 through 2013, is perhaps the most complicated automatic movement ever produced by Seiko. Complications include retrograde day, date by pointer, retrograde power reserve indicator, and independently adjustable 24-hour hand. It was the final development of the Seiko 4S family, which itself was derived from the historic Seiko 52 stream of movements. Cal. 4S36 is similar in design to Cal. 4S76, though it lacks the upscale finishing and regulation of that movement. Unlike most 4S movements, Cal. 4S36 has 50 hour power reserve.
Unlike the related Cal. 4S27, which resembles a chronograph, this movement has a balanced look emphasizing the dual retrograde pointers on each side of the tall quadruple hand stack. A second crown at 2:00 on the dial adjusts the central 12 hour hand in 1-hour increments, leaving the stacked 24 hour hand as “home time.”
- A retrograde pointer at 2:30 shows the day on a “fan”
- A subdial at 6:00 shows the date using a small pointer
- A retrograde pointer at 9:30 shows the power reserve clockwise on a “fan”
Cal. 4S36 was used originally in the Seiko SARN “Luxury Power Reserve” watch series from 2007 through 2013. It also made a short appearance in The Seiko “Complicated” SAEN001 in 2012.
- 2012 Seiko Complicated SAEN001
- 2007-2013 Seiko Luxury Power Reserve SARN001
- 2007-2013 Seiko Luxury Power Reserve SARN003
Complicated Seiko 4S Movements
After 2000, Seiko had more diverse mechanical movements to choose from. The 4S family was moved upmarket as a base for modules to use in complicated upscale watches. The last 4S movement was retired in 2015.
| Production | Watch | Winding | Jewels | Notes | |
|---|---|---|---|---|---|
| 4S27 | 2003-2007 | SAGN | Automatic | 28 | Retrograde day at 2:00 Date pointer at 6:00 GMT subdial at 9:00 |
| 4S29 | 2003-2007 | SAGN | Manual | 29 | Small seconds at 6:00 Retrograde power at 9:00 |
| 4S36 | 2007-2013 | SAEN SARN | Automatic | 31 | Independent 24 hour hand Retrograde day at 2:00 Date pointer at 6:00 Retrograde power at 9:00 |
| 4S76 | 2004-2010 | GBBT GCBT | Automatic | 31 | Independent 24 hour hand Retrograde day at 2:00 Date pointer at 6:00 Retrograde power at 9:00 |
| 4S77 | 1996? 2000-2005 | GCBG | Automatic | 28 | Retrograde day at 2:00 Date pointer at 6:00 GMT subdial at 9:00 |
| 4S79 | 1998-2015 | GBAY GCAY | Manual | 31 | Small seconds at 6:00 Retrograde power at 9:00 |