Cal. 4S79 is a hand-winding movement with small seconds and power reserve indicator produced by Seiko from 1998 through 2015. It was part of the second “wave” of movements in the Seiko 4S family, which itself was derived from the historic Seiko 52 stream of movements. Cal. 4S79 is similar in design to Cal. 4S29, though has two additional jewels as well as upscale finishing and regulation to -10/+15 seconds per day. Two Credor Cal. 4S79 models are the only chronometer-certified and signed watches in modern Seiko history.
The movement has an unusual look thanks to its complications: It has small seconds at 6:00 and a retrograde power reserve indicator at 9:30. This shows the 40 hour power reserve.
Cal. 4S79, used in Credor watches, was produced much longer than the Brightz Cal. 4S29. It first appeared in 1998 in the Credor Pacifique Chronometer GCAY series, then appeared in the Credor GBAY series starting in 2001. It was also used in the rare GZAY999, of which just 20 were produced. After 2005 it was used in the Credor Node GCAY series until 2015. This makes Cal. 4S79 the longest-lived and last surviving member of the Seiko 4S family.
- 1998 Credor Chronometer GBAY992 (Limited Edition of 500 in yellow gold)
- 1998 Credor Chronometer GZAY999 (Limited Edition of 20 in white gold)
- Credor GBAY992
- 2001-2002 Credor GBAY996 (yellow gold)
- Credor GBAY999 (Platinum)
- Credor GCAY886
- 2005-2015 Credor Node GCAY987, GCAY989
- 1999-2002 Credor Pacifique GCAY990, GCAY991, GCAY992, GCAY994, GCAY995, GCAY996, GCAY999
4S79 Certified Chronometers
In 1998, Seiko watchmakers adjusted Cal. 4S79A for chronometer performance, delivering two limited-edition models with chronometer certificates. The Credor GBAY992 was a yellow gold watch issued in a numbered edition of 500. The Credor GZAY999 was a white gold in a limited edition of 20 examples. These 520 watches have the word “chronometer” on the dial, the only such watches from Seiko since the 1970s. They are also the only 4S79 models with a display caseback.
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 |