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You are here: Home / Movements / Seiko 6R20

Seiko 6R20

Last Update: July 7, 2019

Brand:Seiko, Seiko Instruments Inc.
Family:
Seiko 6R Family
Height:6.15 mm
Jewels:29
Reserve:45 hours
Frequency:28,800 A/h
Winding:Automatic, Bi-Directional Automatic Winding, Central Rotor Automatic Winding
Diameter:27.40 mm (12 ligne)
  Complications:Date, Date by Pointer, Day, Day by Pointer, Hacking Seconds, Hand Winding, Power Reserve Indicator, Quick Date Correction
Hands:Central Hour Hand, Central Minute Hand, Central Seconds Hand, Date Pointer at 6:00, Day Pointer at 3:00, Power Reserve Pointer at 9:30
Distinguishing Technical Characteristics
Central-Rotor Automatic
Counter-Clockwise Balance Cock
Etachron Regulator
Balance
Balance at 3:00
Central Rotor
Production: 2007 – Current
1910s 1920s 1930s 1940s 1950s 1960s 1970s 1980s 1990s 2000s 2010s 2020s

Seiko Cal. 6R20 is a midrange automatic movement produced by Seiko Instruments Inc. (SII) for Seiko watches. Like other Seiko 6R movements, it is more refined and accurate than the related Seiko 4R series and uses a Spron 510 mainspring. Unlike Cal. 6R15, it is a “Hi-Beat” movement operating at 28,800 A/h and has complications: Subdial day by pointer at 3:00, subdial date by pointer at 6:00, and clockwise power reserve pointer at 9:30.

Cal. 6R20 was introduced around 2007 and remains in production today. It has 29 jewels and 208 parts. It was the basis for the 8R chronograph movement family. Cal. 6R20 was used in the Premier Automatic watches, models SPB001J1, SPB003J1, and SPB005J1, produced October 2007 through July 2011.

According to Seiko documents, this is a modular movement based on Cal. 6R15 but with a Hi-Beat balance and hacking seconds. Cal. 6R21 is similar but reverses the power reserve indicator to counter-clockwise and moves it to 9:00 on the dial.

JewelsComponentsSpeedPower3:006:009:00
6R152316821,60050Date Window
6R202920828,80045Day SubdialDate SubdialClockwise
Power Reserve
6R212920828,80045Day SubdialDate SubdialCounter-Clockwise
Power Reserve
6R243122428,80045Retrograde DayRetrograde DateClockwise
Power Reserve
6R272928,80045Date SubdialCounter-Clockwise
Power Reserve
6R352421,60070Date Window
Images are taken from official publications and are used here for commentary and educational purposes. Copyright is held by the original owner as noted.
Manufacturer Link

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