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You are here: Home / Movements / Seiko 6R21

Seiko 6R21

Last Update: July 9, 2019

Brand:Seiko, Seiko Instruments Inc., Time Module 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)
© Seiko Cal. 6R21B in Japan-market SARW045 Complications:Date, Date by Pointer, Day, Day by Pointer, Hacking Seconds, Hand Winding, Power Reserve Indicator, Quick Date Correction, Quick Day 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 9:00
Distinguishing Technical Characteristics
Central-Rotor Automatic
Counter-Clockwise Balance Cock
Etachron Regulator
Balance
Balance at 3:00
Central Rotor
Production: 2009 – Current
1910s 1920s 1930s 1940s 1950s 1960s 1970s 1980s 1990s 2000s 2010s 2020s

Seiko Cal. 6R21 is a midrange automatic movement produced by Seiko Instruments Inc. (SII) for Seiko watches. Since 2010, it is also sold by Time Module Inc. (TMI) as Cal. NE20 (or NE20B) for use by other manufacturers. 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 counter-clockwise power reserve at 9:00.

Cal. 6R21 was introduced around 2009 and remains in production today. It has 29 jewels and 208 parts. Cal. 6R21 was used in the Ananta Multi-Hand Automatic watches, models SPB017J1, SPB019J1, and SPB021J1, produced August 2009 through March 2013.

According to Seiko documents, this is a modular movement based on Cal. 6R15 but with a Hi-Beat balance and hacking seconds. Cal. 6R20 is similar but has a clockwise power reserve indicator at 9:30.

Seiko 6R21 Applications

Cal. 6R21 is a rare movement found in only one model as of 2020.

  • Seiko Presage SPB085
Seiko Presage SPB085 with Cal. 6R21C
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.
External Link
Manufacturer Link

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