Seiko 9S51

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	20	"Railway" pocket watch
2002	9S56 8L36	Automatic	28,800	Hour, minute, second, 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 SBGR002, SBGR007, SBGR013, SBGR033
• 9S55 (1998) - Automatic date SBGR001, SBGR003, SBGR005, SBGR009, SBGR011, SBGR015, SBGR017, SBGR019, SBGR023, SBGR025, SBGR027, SBGR029, SBGR031, SBGR035, SBGR037
• 9S54 (2001) – Manual SBGW001, SBGW003, SBGW005, SBGW007, SBGW008, SBGW009, SBGW011, SBGW012, SBGW014, SBGW021, SBGW023; 130th Anniversary SBGW004
• 9S56 (2002) – Automatic GMT SBGM001, SBGM003, SBGM005, SBGM007, SBGM009, SBGM011

External links

• Four Hundred Years After, Part II, The Legacy of Seikosha
• Where My Watch Came From
• Shizukuishi Watch Studio
• Interview: Akira Ohira - watchmaking "Father" of modern mechanical Grand Seiko

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