Seiko 4R36
High confidenceThe 7S26's replacement across the mainstream range, and dimensionally compatible with it — which is why 7S26-era watches are so often found with a 4R36 fitted. The swap is a legitimate and popular upgrade; it is also undisclosed often enough to be worth checking for.
Specifications
- Movement manufacturer
- Seiko
- Production
- 2011–present
- Frequency
- 21,600 vph (3 Hz)
- Jewels
- 24
- Power reserve
- 41 hours
- Winding
- automatic
- Complications
- Day-date · Hacking seconds · Hand-winding
Architecture
Automatic day-date caliber derived from the 7S26 architecture with hacking seconds and manual winding added.
Related calibers
Preceded by
Seiko 7S26The 4R36 adds hacking and hand-winding and fits the same cases.
References using this caliber
- Seiko SRPD53Factory
5 Sports · 2019 →
- Seiko SRP777Factory
Prospex · 2016 →
- Seiko SKX007Aftermarket
5 Sports · Whole production
Provenance of this record
Sources & Evidence
Seiko — Prospex, Presage, 5 Sports and Astron product documentation
Seiko Watch Corporation
- Accessed
- 2026-08-18
Cited for
Seiko caliber technical guides and parts catalogues
Seiko Watch Corporation / Seiko Instruments
- Accessed
- 2026-08-18
Cited for
Last verified: Not yet reviewed