Cal. 4S35 is an automatic movement with date produced for high-end Seiko Automatic watches from 1992 through 1998. It was critical to the development of the modern Grand Seiko mechanical watch series and laid the foundation for the Grand Seiko 9S movement series.
Cal. 4S35 is identical in design to Cal. 4S15 and Cal. 4S25. The only differences are in finishing and regulation, with Cal. 4S35 delivering -10/+15 seconds per day compared to -15/+25 seconds for Cal. 4S15 and 4S25. The early 1993 Seiko catalog lists Cal. 4S35 as being 4.00 mm thick, 0.17 mm thinner than the similar Cal. 4S15. This marks the first appearance of the 4S series in a seiko catalog, though official company sources place the introduction of this movement as 1992.
Cal. 4S35 was used in the Seiko Automatic SCVK series from 1992 through 1998.
