Seiko 4S28

	Brand:	Seiko
	Family:	Seiko 4S Family
	Height:
	Jewels:	24
	Reserve:	40 hours
	Frequency:	28800 A/h
	Winding:	Hand winding
	Diameter:	25.60 mm (11.5 ligne)
	Complications:	Hacking Seconds
	Hands:	Central Hour Hand, Central Minute Hand, Small Seconds Hand at 6:00

Distinguishing Technical Characteristics
Hand-Winding Clockwise Balance Cock Screw Regulator Balance, Balance at 5:00
Production: 1994 – 2000
1910s	1920s	1930s	1940s	1950s	1960s	1970s	1980s	1990s	2000s	2010s	2020s

Cal. 4S28 is a hand-winding movement with small seconds at 6:00. It was developed by Seiko in the early 1990s and is based on the Seiko 52 stream of movements, which had been retired in 1976. Cal. 4S28 is very similar to Cal. 4S24, which has central seconds rather than the subdial. It is also closely related to Cal. 4S15, which is an automatic movement with date.

Cal. 4S28 was notably used in the 2000 Historical Collection Laurel reissue, catalog number SCVM001.

• 1994-1998 Seiko Pocket Watch SCVG001
• 1995-1998 Seiko Pocket Watch SCVG002
• 1996 Seiko Laurel LJAK600 (steel and yellow gold, white dial)
• 1996 Seiko Laurel LJAK601 (steel, blue dial)
• 1996 Seiko Laurel LJAK602 (steel, white dial)
• 2000 Seiko Historical Collection Laurel SCVM001
• 2000 Seiko Laurel SCVM001 (LE of 1000)

Early Seiko 4S Movements

From the 1992 introduction of the Seiko 4S family through the early 2000s, Seiko used the 4S line as a high-end movement for diverse watches, including the SUS military, Alpinist, and Titanium diver. Most of these models were retired shortly after introduction, and the series of simple 4S movements was phased out by 2003.