Seiko 6R15

6R15 is one of a family of modern automatic upper-midrange watch movements from Seiko. The 6R15 is also sold as the NE15A. A "high beat" derivative with a chronograph module is also available, called the Seiko 8R28.

Overview

The 6R15 family was introduced in 2006 as a higher-spec derivative of the familiar Seiko 7S26. It was intended to replace the expensive "high beat" King Seiko-derived 4S15 in mainstream watches, allowing that family to be used exclusively in more expensive models.

The 6R is an automatic movement which adds hacking and hand winding to the existing 7S26 base. This is the main difference between the movements: The winding works now include two separate pinions on the bottom plate to add hand winding. It also features a hacking mechanism and pinned balance spring for adjustability. Thanks to a Spron 510 mainspring, the 6R15 boasts 50 hour power reserve, and the faster-beating 6R2x series has a 45 hour power reserve.

The 6R20 differs from the base 6R15 in many ways. It beats at 28,800 vph and features a power reserve indicator and both day and date in a window. The derived 6R21 and 6R24 also beat at 28,800 and have power reserve indicators but add day and date on subdials (sweep for the 6R21 and retrograde for the 6R24).

As of 2018, the 6R15 is used in the Seiko Prospex SBD series of watches, which start at $600, as well as the higher-end Prospex and Presage SPB and Seiko Core SDG.

Variants

Movement	Beat	Winding	Hands	Date	Subdial	Jewels	Power reserve
6R15	21,600	Automatic	Hour, minute, seconds	Date window	None	23	50 hours
6R20	28,800	Automatic	Hour, minute, seconds	Day and date window	Power reserve indicator	29	45 hours
6R21		Automatic	Hour, minute, seconds	Sweep day and date subdials	Power reserve indicator
6R24		Automatic	Hour, minute, seconds	Retrograde day and date subdials	Power reserve indicator	31
6R27		Automatic	Hour, minute	Sweep date subdial	Sweep date, retrograde power reserve indicator	29

Applications

The Seiko 6R15 is commonly found in upper-midrange models, but was also used in Seiko's 100th anniversary "Laurel" tribute, SARX011. 6R27 is very rare, only used in the 100th anniversary "Laurel" tribute, SARW005.

By Model Line

• 6R15
  • SARB "Cocktail Time" and "Alpinist", SARG, SARX "Presage", SBDC "Field Master"
• 6R27
  • SARW "Presage"

External links

• Inside the Seiko 6r15 with a comparison to the 7S26
• Seiko 4R36 -The Family In Brief
• Seiko 6R15 Manual
• Seiko 6R20, 6R21, 6R24, 6R27 Manual
• Seiko 6R Family Reference

Description: Automatic movement Functions: Hacking Hand winding Automatic bidirectional winding Diashock Hours, minutes, seconds Quickset date Data: Diameter: 12 ligne (27.4 mm), Height: 5.32 mm 23 jewels 21,600 A/h Power reserve: 50 hours Production period: Since 2006