Grail Watch Reference

A Reference Library for Watches from Grail Watch

Seiko 6L75

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Cal. 6L75 is a thin automatic watch movement from Seiko, the latest in the Seiko 4L/6L family. Introduced in 2019, it measures just 3.69 mm thick and is designed to compete head-to-head with the Swiss ETA 2892A2.

Cal. 6L75 is used in the Credor GCCD watch lines:

  • 2019-present Credor Signo GCCD998
  • 2019-present Credor Signo GCCD997
  • 2019-present Credor Signo GCCD995
  • 2020 Credor Linealx GCCD993 (LE of 60)
  • 2020 Credor Linealx GCCD991
  • 2020 Credor Linealx GCCD989
  • 2020 Credor Signo GCCD987 (LE of 45)
  • 2020 Credor Signo GCCD985 (LE of 45)

Seiko 8R48

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Cal. 8R48 is an automatic column wheel chronograph movement from Seiko produced since 2014. It is part of the 8R family of movements used in brands such as Presage and Brightz. It is very similar to the rare Cal. 8R49.

  • 2018 Seiko Presage Prestige SARK011
  • 2018-present Seiko Presage Prestige SARK013
  • 2015-2016 Seiko Brightz Mechanical Chronograph SDGZ009
  • 2015-2016 Seiko Brightz Mechanical Chronograph SDGZ011
  • 2015-2016 Seiko Brightz Mechanical Chronograph SDGZ012
  • 2014-2015 Seiko Brightz Mechanical Chronograph SDGZ013 (LE of 500)
  • 2015 Seiko Brightz Mechanical Chronograph SDGZ015 (LE of 500)
  • 2015-2016 Seiko Brightz Mechanical Chronograph SDGZ017
  • 2015-2016 Seiko Brightz Mechanical Chronograph SDGZ019
  • 2015-2016 Seiko Brightz Mechanical Chronograph SDGZ021 (LE of 500)
  • 2016 Seiko Presage 60th Anniversary Enamel Automatic Chronograph SRQ019 (LE of 1000)
  • 2016 Seiko Presage 60th Anniversary Lacquer Automatic Chronograph SRQ021 (LE of 1000)
  • 2017-2019 Seiko Presage Prestige Enamel Automatic Chronograph SRQ023J1
  • 2017 Seiko Presage Prestige Automatic Chronograph SRQ025J1
  • 2020 Seiko Automatic Chronograph 50th Anniversary LE SRQ029
  • 2020 Seiko Chronograph 55th Anniversary LE SRQ031

Seiko 8R Family

CalibreProductionHeightJewelsComponentsModelsNotes
8R28A2008-current7.2 mm34292SRQ
SAEK
SAGK
SDGZ
8R39A
NE88A		2011-current7.6 mm34306SRQ
SAEK		Thicker, for dive watches
8R48A
8R49A		2014-current7.5 mm34311SRQ/SARK
SDGZ		Japan-only
NE86A2014-current7.63 mmOEM2-subdial

Norqain NN20/1

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Cal. NN20/1 is an automatic movement with date produced for Norqain by Kenissi. It is similar to the Tudor Cal. MT5402 but lacks the anti-magnetic silicon hairspring and features a different rotor and finishing.

There has been some controversy regarding the exact specifications of the two Norqain “in-house” movements, but these have been reduced with the release in July 2020 of the Freedom line which uses them. Cal. NN20/1 is smaller and based on the newer Cal. MT5402, while Cal. NN20/2 is much larger and based on the different Cal. MT5652. The difference in size is clearly visible when comparing the movements cased in the 39 mm Norqain Freedom watches.

There has been some controversy regarding the exact specifications of the two Norqain “in-house” movements, but these have been reduced with the release in July 2020 of the Freedom line which uses them. Cal. NN20/1 is smaller and based on the newer Cal. MT5402, while Cal. NN20/2 is much larger and based on the different Cal. MT5652. The difference in size is clearly visible when comparing the movements cased in the 39 mm and 40 mm Norqain Freedom watches.

Cal. NN20/1 in the 39 mm Freedom 60 39
Cal. NN20/2 in the 40 mm Freedom 60 GMT

Norqain has been open about the fact that their “in-house” NN20 movements are produced by Kenissi, and issued a press release affirming this partnership. Many have criticized the company for calling the movements “in-house” since they are clearly produced by a third party and based on their design.

Note: Contrary to the official data sheet shown below, Cal. NN20/1 has 27 jewels.

Tudor MT54 Family Overview

Tudor’s MT54 family appeared in 2018 with the introduction of Tudor’s compact Cal. MT5402. Measuring just 26 mm in diameter (11 ligne), which movement was used in the smaller Black Bay Fifty-Eight 39 mm watch models. Once production was underway at the new joint venture manufacture in Le Locle, Kinessi, specialized versions were created for Chanel and Norqain, Cal. 12.1 and NN20/1, respectively.

Chanel 12.1
Tudor MT5402
Norqain NN20/1

All three movements share the same architecture but differ dramatically in execution. The most obvious difference is the use of brand-specific winding rotors, with Chanel’s offset circle motif particularly striking. The Chanel Cal. 12.1 is also available with a date complication (and an extra jewel) though the name remains the same. Chanel’s movement also appears to be a bit reduced in diameter compared to the Tudor movement, though not by more than a few tenths of a millimeter.

Norqain NN20/2

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Cal. NN20/2 is an automatic GMT movement with date produced for Norqain by Kenissi. It is similar to the Tudor Cal. MT5652 but lacks the anti-magnetic silicon hairspring and features a different rotor and finishing.

There has been some controversy regarding the exact specifications of the two Norqain “in-house” movements, but these have been reduced with the release in July 2020 of the Freedom line which uses them. Cal. NN20/1 is smaller and based on the newer Cal. MT5402, while Cal. NN20/2 is much larger and based on the different Cal. MT5652. The difference in size is clearly visible when comparing the movements cased in the 39 mm and 40 mm Norqain Freedom watches.

Cal. NN20/1 in the 39 mm Freedom 60 39
Cal. NN20/2 in the 40 mm Freedom 60 GMT

Norqain has been open about the fact that their “in-house” NN20 movements are produced by Kenissi, and issued a press release affirming this partnership. Many have criticized the company for calling the movements “in-house” since they are clearly produced by a third party and based on their design.

Seiko 9S5x Family

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Seiko introduced the flagship 9S family of movements in 1998 for their growing Grand Seiko line. Similar movements under the 8L name were later used in the Brightz, Credor, Galante, and Prospex lines. It was a modern 28,800 A/h movement with Seiko’s signature Magic Lever bi-directional winding system.

See also the Seiko 9S8x family of hi-beat movements.

ProductionApplicationWindingJewelsNotes
8L212003-2007Brightz SAGLAutomatic24Similar to 9S51
8L342000Railway pocket watchManual20Small seconds
8L352000-presentBrightz SAGQ
Prospex SBDX
Prospex SLA		Automatic26Date, similar to 9S55
8L362011-presentCredor GCBZ
Galante SBLM		Automatic27GMT, similar to 9S56
8L382010-2015Galante SBLLAutomatic26Open Heart
8L75-2005Credor GCBRAutomatic26Date, similar to 9S55
9S511998-2009GS SBGRAutomatic24No date
9S542001-2010GS SBGWManual20No date
9S551998-2010GS SBGRAutomatic26Date
9S562002-2010GS SBGMAutomatic27GMT, no date

Seiko 9S8x Hi-Beat Family

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The Grand Seiko 9S85 and 9S86 family are modern automatic “hi-beat” movements. The family was developed in the 2000s as a return to the Hi-Beat tradition of Grand Seiko models like the famous 45GS, 61GS, and 19GS of the 1960s. The movement design is also used by Credor and Prospex, under the 8L name.

The first modern Hi-Beat movement from Seiko was the limited-production “Super Hi-Beat” Cal. 8L88. Introduced at Baselworld in 2006, this movement ran at 12 Hz (43,200 A/h) and was used in the Credor GBBX998.

© 2015 Seiko

Cal. 9S85 was introduced in 2009 as the first modern Hi-Beat movement for Grand Seiko and was joined in 2014 by Cal. 9S86, which adds an independently-adjustable 24 hour GMT hand. They operate at the traditional Hi-Beat rate of 10 Hz (36,000 A/h).

The 9S movements are finished to the standard of the modern Grand Seiko 9S family and feature many technological advancements. They were the first movements to use MEMS technology for ultra-fine finishing of the escape wheel and pallet fork, and they use proprietary Spron alloys for the hairspring (Spron 610) and mainspring (Spron 530).

In 2019, Seiko introduced a lower-finished version of Cal. 9S85 for the Prospex SLA025 Hi-Beat dive watch. This Cal. 8L55 is otherwise similar. Grand Seiko also introduced a V.F.A. version of Cal. 9S85 tuned to deliver -1/+3 seconds accuracy.

A new generation, the Grand Seiko 9SA family, appeared in 2020. These new “80 hours” movements are hi-beat automatics with a longer power reserve, free-sprung balance, and double-impulse escapement.

CalibreProductionSpeedJewelsFunctionsModels
Cal. 8L552015-present36,00037DateProspex SLA/SBEX
Cal. 8L882008-200943,20041Power reserveCredor GBBX998
Cal. 9S852009-present36,00037DateGrand Seiko SBGH
Cal. 9S862014-present36,00037Date, GMTGrand Seiko SBGJ

Seiko 9S6x Family

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Seiko 9S6x Family Overview

9S is the family of high-end mechanical watch movements used in the Grand Seiko and Credor watch lines. The current “3 days” 9S6x family debuted in 2006 with Cal. 9S67, and has replaced the Seiko 9S5x series over the following decade. The movement boasts 72 hours of power reserve thanks to a stronger Spron 510 or 610 mainspring and escape wheel and pallet form finished with MEMS technology.

Seiko boasts that these movements can deliver -3/+5 seconds per day accuracy in controlled static tests. On the wrist, the company claims -1/+10 second accuracy per day, and Seiko adjusts them in 6 positions. Adjustment is performed using a screw with index moving a mobile regulator for the flat hairspring.

The 9S family movements are constructed by hand at Seiko’s Shizukuishi Watch Studio in Morioka, Iwate Prefecture, Japan.

All watches in the 9S6x series feature hand winding, hacking seconds, and operation at 28,800 A/h. Most feature automatic winding with a central rotor mounted on five ball bearings. These use a conventional reverser wheel rather than the Seiko Magic Lever system found on the previous Cal. 9S5x series.

Seiko 9S6x Family

ProductionModelsWindingJewelsDateNotes
Cal. 9S612015-presentSBGRAutomatic33No
Cal. 9S632019-presentSBGKManual33NoPower reserve at 3:00
Small seconds at 9:00
Cal. 9S642011-presentSBGWManual24No
Cal. 9S652010-presentSBGRAutomatic35Yes
Cal. 9S662010-presentSBGMAutomatic35YesCentral GMT hand
Cal. 9S672006-2010SBGLAutomatic41YesPower reserve at 3:00
Cal. 9S682017-presentSBGRAutomatic35YesLarger size

See Also: Seiko 9S6x Family

Seiko 6S Family

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A key part of Seiko’s resurgence in modern times was the Cal. 6S family of automatic chronograph movements. Although rarely seen, they demonstrated the company’s expertise along with the Cal. 9S movement family introduced at the same time.

Seiko called back many original watchmakers from retirement to develop the “phoenix” Cal. 6S78 movement. On introduction in 1998, it helped re-establish the company’s bona fides and was a halo offering for the domestic Credor brand. It is thoroughly modern, with a vertical clutch and column wheel, yet classical in look. It has a 6-9-12 subdial arrangement like the popular Valjoux 7750 family. Many models feature a date or power reserve complication as well, and hand-winding versions were also produced.

  • 6S78 (1998-2004) – 34 jewels, automatic, date, Credor
  • 6S28 (2005-2013) – 34 jewels, automatic, date, Credor
  • 6S37 (2001-2016) – 40 jewels, automatic, date, power reserve, Prospex/Brightz/Credor
  • 6S77 (2003-2005) – 40 jewels, automatic, date, power reserve, Credor
  • 6S96 – 38 jewels, automatic, no date, power reserve
  • 6S74 – 35 jewels, hand winding, no date, power reserve
  • 6S99 (2002-2005) – 35 jewels, hand winding, no date, power reserve, skeletonized

Seiko 8R Family

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Seiko 8R is a family of modern chronograph movements with advanced features like a column wheel, vertical clutch, and three-pointed reset hammer. Although newer and numerically higher than the Seiko 6S chronograph, it is considered to be slightly lower in terms of refinement and design. The 8R family is sold by Time Module Inc. (TMI) as Cal. NE86 and NE88 for use by third-party watch makers.

The 8R family was introduced in 2009 shortly after the related 6R family of automatic non-chronograph movements. Both use the proven 7S gear train and Seiko’s Magic Lever winding system. It is built on the 6R20 but is much more integrated than a traditional modular chronograph movement. Unlike the 6S, the 8R family uses a 3-6-9 subdial arrangement, albeit with running seconds at 3:00 rather than 9:00 as is traditional. The date window is placed at an angle at 4:30.

Seiko was the first to market with a vertical clutch column wheel chronograph in 1969 with Cal. 6139 and the company takes these technologies to a new level in Cal. 8R. Rather than driving the minute and hour counters from the chronograph seconds wheel, each is driven by a powered wheel with its own clutch. A unique three-pointed hammer starts, stops, and resets all three wheels simultaneously, and all the counters advance continuously rather than only at one-minute intervals.

Cal. 8R28 is the most common movement in the family and the first introduced. It is 7.2 mm thick, has 34 jewels and 292 components, and was used in the SRQ009/SRQ011 Ananta, SAGK001 and SDGZ001 Brightz, and SRQ001 Velatura. Introduced in 2011, Cal. 8R39 is 7.6 mm high and was made for dive watches, including the exclusive SRQ013 Ananta limited edition. Cal. 8R48 appeared in 2014 and has similar specifications but is made from 311 components and measures 7.5 mm thick. It was only used in Japan-market Brightz watches and the rare SRQ021 60th anniversary Laurel and SRQ023 Presage watches of 2016. Cal. 8R49 is nearly identical to 8R48.

TMI also sells an OEM version of Cal. 8R39 called NE88. Introduced in August 2014, it is listed at 7.63 mm thick. Cal. NE86 is similar but lacks the hour counter at 6:00, moving the date window there. TMI rates these movements as accurate to -15/+25 seconds per day.

Seiko 8R Family

CalibreProductionHeightJewelsComponentsModelsNotes
8R28A2008-current7.2 mm34292SRQ
SAEK
SAGK
SDGZ
8R39A
NE88A		2011-current7.6 mm34306SRQ
SAEK		Thicker, for dive watches
8R48A
8R49A		2014-current7.5 mm34311SRQ/SARK
SDGZ		Japan-only
NE86A2014-current7.63 mmOEM2-subdial

ETA Flatline 2890 Family

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ETA 2890 Family Overview

The ETA 2890 family is a series of slim and robust automatic watch movements produced by ETA. They are generally regarded as superior to the similar ETA 2800 family. Cal. 2890 and its successors is based on the Eterna 1466U, with ball bearings on the rotor and a smaller balance wheel in the modern style. Launched in 1975, the family remains one of the leading watch movements to this day.

The most well-known movement in this series today is Cal. 2892A2, a highly evolved automatic movement with central seconds and a date wheel. Because of its slim dimensions, Cal. 2892A2 is often paired with modules to add world time, power reserve indicator, chronograph, and other complications.

Distinguishing features of the ETA 2890 family include a smaller balance wheel than historic movements, including the ETA 2824 family, and a large rotor hub located with seven visible bearings. The balance is located at 12:00 when viewed from the back with the crown at 9:00, and is located by a clockwise cock with an eccentric screw for regulation.

Most members of the modern 2890 family are available in there finish levels:

  • Elaboré – with nickel balance
  • Top – with Glucydur balance
  • Chronomètre – with Glucydur balance and official chronometer certification

ETA also sells these movements with gold plating, various finishes, and custom rotors.

This 2004 ETA advertisement shows a “Family Portrait” of the modern 2890 series

ETA 2890 Family

Most current ETA 2890 family movements have been updated since the 1990s with improved winding efficiency and an extra jewel in the upper winding bridge. As of 2020, ETA is no longer supplying these movements outside the Swatch Group, with most buyers switching to the clone SW300 family from Sellita. Specifically, Cal. SW300-1 replaces ETA’s 2892A2, Cal. SW330-1 replaces ETA’s GMT 2893-1, and Cal. SW360-1 replaces ETA’s small seconds 2895-2.

ComplicationsFirst Generation
1975-1983		Second Generation
1983-2000		Third Generation
1996-present
No DateETA 2890 (12.5”’)
DateETA 2892 (12.5”’)ETA 2892-2ETA 2892A2
World Time Disc, DateETA 2893-1
Adjustable 24 Hour Hand, DateETA 2893-2
World Time Disc, No DateETA 2893-3
Modular Chronograph, Small Seconds, DateETA 2894-2 (12.5”’)
ETA 2894S2 (12.5”’)
Small Seconds, DateETA 2895-1ETA 2895-2
Dual Concentric Wheel DateETA 2896
Power Reserve Indicator, DateETA 2897
Perpetual Calendar, Moon Phase, No SecondsETA 2890-9ETA 2890A9
Perpetual Calendar, Moon Phase, Central SecondsETA 2891-9ETA 2891A9

ETA 2893 Movements

ETA released a trio of dual time zone movements in 1992, all known as Cal. 2893. Each movement has a slightly different implementation of a 24 hour second time zone display.

DateNo Date
24 Hour DiscETA 2893-1ETA 2893-3
24 Hour HandETA 2893-2

In all three movements, the central 24 hour display is quick-set using the crown in second position and is independent of the central hour hand, which is set using the crown in third position. Adjusting the 24 hour hand or disc does not cause the movement to “hack” or stop, so the timekeeping remains accurate when traveling. Although common today, an independent 24 hour hand like this was somewhat unusual at the time. Indeed, the popular Rolex GMT-Master II Ref. 16710 had just gained an independently-adjustable 24 hour hand four years earlier.

This 1992 coverage in Europa Star shows all three members of the ETA 2893 “Travel Time Trio”
Image: Europa Star 193, 1992

ETA 2890 Family History

See Also: Confirming the ETA 2892 Timeline

This 1975 advertisement in Europa Star shows the key movements in the Ebauches SA family: ETA 2678, AS 5103/5106, ETA 2783, ETA 2824, AS 2063/2066, ETA 2878, FHF 411/412, ETA 2892, AS 5008, and VAL 7750

The original ETA 2890 and 2892 were introduced in 1975 and produced through 1983. These measured 12.5”’ (28.0 mm) in diameter and were designed to be ultra-thin (marketed as “Flatline”) with the option to be used as a base for modular complications. One novel design feature is the fact that the automatic winding gear extends into the base movement, keeping the total profile to just 3.6 mm regardless of whether or not a date complication is fitted. This system used ball bearings for durability, which ETA called “Etarotor”.

They are based on Eterna’s Cal. 1466U, designed by Heinrich Stamm. This movement proved difficult to manufacture, so a talented young engineer, Anton Bally, was given the task of redesigning it for wider use across many brands. The resulting Cal. 2892 was improved in nearly every way while keeping many of Stamm’s signature elements, including the ball bearing rotor, sunken winding mechanism, and tapered edges. Bally later based the quartz Cal. 940 on the 2892 design as well.

The family was revised in 1983 with a narrower 11.5”’ (25.6 mm) width. Most aspects of the design remained, though the no-date 2890 was dropped and official modular movements added to the ETA 2892-2 base: ETA 2893-1 and ETA 2893-3 have a “world time” disc, ETA 2893-2 has an adjustable 24 hour hand, ETA 2894-2 was a modular chronograph, ETA 2895-1 had small seconds, and ETA 2890-9 and ETA 2891-9 had a perpetual calendar mechanism with moon phase. Of these, only the world time ETA2893 series and chronograph ETA 2894-2 remain in production as of 2020.

The third generation appeared in 1996 with the ETA 2892A2. The modification was focused on winding efficiency, with a reduced chamfer increasing the mass of the winding rotor and the switch from a stud to a jewel in the upper winding bridge for the intermediate wheel. Although the small seconds and perpetual calendar movements were updated (ETA 2895-2, ETA 2890A9, and ETA 2891A9), the chronograph remained in production as-is. New movements were also added: ETA 2896 has a “big date”, and ETA 2897 has a power reserve indicator.

The original ETA 2892 measured 12.5”’ (28.0 mm) in diameter

The revised ETA 2892-2 measured 11.5”’ (25.6 mm) in diameter
Today’s ETA 2892A2 also measures 11.5”’ but features improvements to the winding system

From Mechanical to Quartz

In the 1970s, ETA Director Fritz Scholl decided to bring together the mechanical capabilities of ETA with the electronics leadership of EEM and the CEH. This project would bring ETA into the quartz era by adding quartz timing and a Lavet stepper motor to existing mechanical wheel trains. This task largely fell on talented engineer Anton Bally, who had created the ETA 2892 movement and would become Chairman and President of ETA in 1985.

Bally’s first quartz movement was Cal. 9362, the first Swiss movement with a Lavet stepper motor. It was based on the day-date Cal. 2872 of the ETA Gabarit family, the thickness of which gave extra room to integrate this new timing technology. But the date complication was derived directly from that in Cal. 2836, an earlier ETA design. The stepper motor was produced in Switzerland based on the design of French firm Léon Hatot and the integrated circuit came from ETA partner Faselec. The similar Cal. 9361 lacked the day wheel. These were sold under the “Swissonic” name in 1976 but was called “Gabarit Quartz” by 1978.

Bally next turned to his recent “Flatline” design to create a thinner quartz movement. Cal. 940 used the hour and minute wheel, setting mechanism, and date complication of Cal. 2892 along with a new thin rotary stepper motor and 32 KHz quartz crystal. This was also initially sold under the “Swissonic” name in 1976 and 1977, but Cal. 940 would use the “Flatline Quartz” name after this.

Bally also developed a compact quartz movement for ladies watches. The 7.75 ligne Cal. 950 was based on ETA’s Cal. 2512 and measured just 3.1 mm thick. This made it one of the smallest quartz movements created to date by any company or nation.