Seiko · 4R series
4R36
The day-date 4R automatic familiar from Seiko 5 Sports, with manual winding and stop seconds.
At a glance
- Type
- Automatic mechanical
- Display / complication
- Day-date
- Architecture
- Automatic winding, day and date calendar
- Timebase
- 21,600 vph / 3 Hz
- Power reserve
- Approx. 41 h
- Jewels
- 24
Reference sources reviewed 7 November 2026. Published specifications, not independent measurements. Versions and complete-watch specifications can differ; fields without a verified figure are omitted or identified.
Find it in a watch
Seiko 5 Sports SRPD55
An example from the linked references. Check the exact model and production generation.
What distinguishes it
Look beyond the reference.
The weekday adds a second everyday calendar indication to the 4R35’s basic layout. Seiko specifies 24 jewels for this version.
For the enthusiast
The SRPD55 is a concrete example; other watches may package the same calibre differently. Compare with TMI NH36, but preserve the manufacturer’s exact reference when discussing specification or replacement parts.