The enigmatic 4s movement

[Updated 5 Feb 2015: Please refer here for a sequel to this post. ]

Seiko fans will no doubt know,  heard about or even handled a watch with the 4s movement, or its predecessor the illustrious Daini 52 movement. A good introduction can be found here by our fellow friends in the NZ timekeeper forum.

Here’s a brief chronicle of the 4S Series from the NZ timekeeper post.

1970 Cal. 5206 LORD MATIC (LM)
1971 Cal. 5246 KING SEIKO (KS) Vanac
1971 Cal. 5246 KING SEIKO (KS) Chronometer
1972 Cal. 5206 LM Special
1973 Cal. 5256 KING SEIKO (KS) Vanac Special
1976 52 Stream discontinued
—————————————————–
1992 52 resurrected and re-designated 4S
1992 4S35
1995 4S15 Alpinist, 4S15 Titanium Diver
1996 4S15 SUS Military
1996 4S77 CREDOR Retrograde (GMT)
1997 4S12 SUS (GMT)
1997 4S15 Alpinist, SUS, and Titanium Diver discontinued
1998 4S12 SUS discontinued
2000 KING SEIKO 4S15 Historical Re-issue LE
2002 4S Series now limited to BRIGHTZ and CREDOR
2003 4S27 BRIGHTZ
2004 4S76 CREDOR Node
2007 4S Series now limited to CREDOR
2007 4S36 GMT Retrograde

The two most famous and widely pursued watches containing the modern 4s movements are the SUS military with the basic 4s15 movement and the SUS GMT with the 4s12 GMT movement.

Throughout my watch days I never thought that the 4s15 came in different grades but apparently they did. Most curious is the fact that the only King Seiko reissue in modern days in the Seiko Year 2000 historical collection was using the 4s15 movement.

Imagine my surprise that higher grades of the 4s15 movement exists in the form of the 4s25 and the 4s35. All three are simple 3 hand movements (all 3 movements appear to be Date only, with 25 jewels) , and the only difference appears to be the better finishing and tighter (unable to confirm) specifications of the 4s35.

The 4s35 has been likened to the Top grade of ETA 2892 (which is basically an uncertified chronometer). With this fact in mind, it is certainly curious that the 4s15 and not the 4s35 was used for the KS reissue.

Update 21 Dec 2013: It can be confirmed that the 4S35 is a more tightly adjusted version of the 4S15 and 4S25, being adjusted to +15/-10 as versus +25/-10. There appear to be no difference between 4S15 and 4S25 on paper.

A somewhat vintage 4s25 watch (released in 1993) came to my attention recently, which led me to discover the 4sX5 movement family.

Unfortunately due to the overwhelming popularity of 4s15 and 4s12 movement, many people are not aware of the other movements in the basic 4s family. A search on the Internet will also not yield much information.

Together with the fact that the 4s movements were used in watches released mainly in the late 90s and early 2000s, perhaps the 4s25 and 4s35 are destined to be forgotten alongside the many great calibers produced by Seiko in their long history of independent watch making.

[Updated 5 Feb 2015: Please refer here for a sequel to this post. ]

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