====== Seiko 9S51 ======

{{wst>author|[[Foskett, Stephen|Stephen Foskett]] ([[https://grail-watch.com/|Grail Watch]])}}

The **9S5x** family of high-end watch movements was the flagship mechanical watch product of [[Seiko]] from [[1998]] until the introduction of the "3 Days" power reserve **9S6x** movements after [[2006]]. This range also includes the **8L** family of movements, which are used in Seiko Credor, Prospex, Brightz, and Galante models.

The **8L/9S** family is intended to compete with limited-production Swiss movements from companies like [[Rolex]]. Most are [[automatic]], unlike the ultra-thin [[Seiko 6800]] family, though there are manually-wound versions. The 9S family are carefully finished with Tokyo Stripes and rhodium plating and are adjusted to six positions, while the 8L family has a brushed and gilt finish, with [[colimaconnage]] on the rotor, and is unadjusted. "9S" models are only used in Grand Seiko watches, while "8L" models are used in other ranges.

The 9S5x family includes many notable Seiko movements 

  * [[1998]] reintroduction of mechanical [[Grand Seiko]] models after over 20 years with the 9S51/9S55
  * [[2001]] introduction of the hand-wound 9S54
  * [[2002]] launch of the [[GMT]] 9S56, a first for the family, and was followed later by a rare Credor twin, the 8L36

The Calibre 8L and 9S families are assembled at Seiko's [[Shizukuishi Watch Studio]] in Morioka, Iwate prefecture, Japan, along with other high-end Seiko movements.

===== Initial 9S5x and 8L Movements =====
The first members of this family were introduced in [[1998]]. Although fairly basic in terms of complications, they demonstrated Seiko's manufacturing capability and suggested that the company was committed to the high-end watch market once again.

The basic movements in this initial series are as follows 

  * The first introduction was the non-date 9S51 (and similar 8L21) and dater 9S55 (and similar 8L35 and 8L75)
  * A hand-winding version was introduced in 2001, the 9S54; a similar 8L34 had sub seconds and was used in a "Railway" pocket watch
  * The GMT version came in 2002, the 9S56, and a rare 8L36 variant was used in a Credor "Signo" GCBZ995/GCBZ999 model
  * One rare variant is the "Rolling Stones" 8L38 with an "[[open heart]]" design

==== 9S5x and 8L Movements ====
^Year ^Movement ^Winding ^Beat ^Hands ^Date ^Subdial ^Jewels ^Notes ^
|1998 |9S51\\ 8L21 |Automatic |28,800 |Hour, minute, seconds |None |None |24 |Grand Seiko, decorated with Tokyo stripes, rhodium plated\\ 8L21 is the less-decorated and unadjusted Brightz version from 2005 |
|1998 |9S55\\ 8L35, 8L75 |Automatic |28,800 |Hour, minute, seconds |Date window |None |26 |Grand Seiko, decorated with Tokyo stripes, rhodium plated\\ 8L35 and 8L75 are the less decorated and unadjusted Prospex/Brightz versions |
|2001 |9S54 |Manual |28,800 |Hour, minute, seconds |None |None |20 |Grand Seiko, Tokyo stripes, rhodium plated |
|2001 |8L34 |Manual |28,800 |Hour, minute |None |[[small_seconds|Small seconds]] |20 |"Railway" pocket watch |
|2002 |9S56\\ 8L36 |Automatic |28,800 |Hour, minute, second, [[gmt|GMT]] |None |None |27 |Grand Seiko\\ 8L36 was a rare Credor Signo version |
|2012? |8L38 |Automatic |28,800 |Hour, minute, seconds |None |Open heart |26 |Galante SBLL017 "Rolling Stones", rhodium plated, fausses cotes decoration |

==== 9S5x Applications ====
  * 9S51 (1998) - Automatic [[Grand Seiko SBGR|SBGR002, SBGR007, SBGR013, SBGR033]]
  * 9S55 (1998) - Automatic date [[Grand Seiko SBGR|SBGR001, SBGR003, SBGR005, SBGR009, SBGR011, SBGR015, SBGR017, SBGR019, SBGR023, SBGR025, SBGR027, SBGR029, SBGR031, SBGR035, SBGR037]]
  * 9S54 (2001) -- Manual [[Grand Seiko SBGW|SBGW001, SBGW003, SBGW005, SBGW007, SBGW008, SBGW009, SBGW011, SBGW012, SBGW014, SBGW021, SBGW023; 130th Anniversary SBGW004]]
  * 9S56 (2002) -- Automatic GMT [[Grand Seiko SBGM|SBGM001, SBGM003, SBGM005, SBGM007, SBGM009, SBGM011]]


{{wst>template_seiko_9s_family}}

===== External links =====
  * [[http://people.timezone.com/library/cjrml/cjrml0024|Four Hundred Years After, Part II, The Legacy of Seikosha]]
  * [[http://fnord.phfactor.net/2008/03/20/where-my-watch-came-from/|Where My Watch Came From]]
  * [[http://www.shizukuishi-watch.com/eng/products.html|Shizukuishi Watch Studio]]
  * [[http://www.watchprosite.com/show-forumpost/fi-657/pi-5568098/ti-824423/t--interview-akira-ohira-watchmaking-father-of-modern-mechanical-grand-seiko/|Interview: Akira Ohira - watchmaking "Father" of modern mechanical Grand Seiko]]


<WRAP ud ud_mov>

**Description:**
  * [[Manual winding]] or [[automatic]]

**Functions:**
  * Hours, minutes, seconds
  * [[Small seconds]]
  * [[GMT]]
  * Date window

**Data:**
  * 20, 24, 26, 27, or 41 [[jewels]]
  * 28,800 A/h

**Production period:**
  * [[1998]]-Present
</WRAP>

{{tag>Movements Automatic_movements Manual_winding_movements GMT_movements Seiko_calibres}}