Seiko 6R21

	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