NH35 vs NH36: Choosing the Right Movement for Your Build
The Short Answer
The NH35 has a date only. The NH36 adds a day-of-week display. Both are automatic, both hand-wind, both hack, both run at 21,600 vibrations per hour with roughly 41 hours of power reserve, and both fit the same cases. The choice comes down to one question: does your dial have a day window?
Shared Platform, Different Calendar
The NH35 and NH36 are the same movement family with different calendar modules. The NH35 corresponds to Seiko's 4R35; the NH36 corresponds to the 4R36. They are sold to the aftermarket and to microbrands, while Seiko keeps its branded equivalents for its own watches.
Because the base platform is identical, all the core behaviour is identical:
- Winding: automatic via rotor, plus manual winding through the crown
- Hacking: the seconds hand stops when the crown is pulled, allowing precise setting
- Beat rate: 21,600 vph (3 Hz)
- Power reserve: approximately 41 hours
- Jewels: 24
- Dial seat: 28.5mm
When to Choose the NH35
Choose the NH35 for the overwhelming majority of builds. Almost every aftermarket dial is cut for a date-only movement, so the NH35 gives you the widest choice of dials and the cleanest layout. If you are building your first watch, this is the default and there is no reason to complicate it.
The NH35 is also the correct choice when the dial has a date window at three o'clock and nothing else. Fitting an NH36 behind a date-only dial wastes the day complication and can leave the day disc visible through a gap if the dial opening is generous.
When to Choose the NH36
Choose the NH36 only when the dial genuinely has both day and date windows. This is common on dive-style dials with a day-date aperture at three o'clock. The NH36 also offers day wheels in different languages, including English, Japanese (Kanji), and Arabic, which is a small detail that some collectors value.
Fitting an NH35 behind a day-date dial creates a visible mismatch: one window will sit empty, which looks like a defect rather than a design choice.
The Crown Position Detail
Both movements come in 3 o'clock and 4 o'clock crown versions. This matters more than most beginners expect. If you fit a 3 o'clock movement into a 4 o'clock case, the day and date will sit off-centre in the dial windows. Always match the movement's crown position to the case.
Neither Is Better
There is no quality hierarchy here. The NH36 is not an upgrade over the NH35; it is the same movement with an additional calendar function. Paying more for an NH36 in a date-only build buys you nothing visible.
Related Movements Worth Knowing
- NH34: adds a GMT hand for a second time zone; taller hand stack and wider centre post, so dials may need modification
- NH38: no date, for clean dials and open-heart designs
- NH70/NH71/NH72: skeletonised movements with 30.8mm dial seats, not interchangeable with 28.5mm dials
FAQ
Can I put an NH36 in a case designed for an NH35?
Yes, the case fit is the same. The constraint is the dial: an NH36 needs a dial with both day and date windows, and the crown position must match.
Is the NH36 more accurate than the NH35?
No. They share the same base movement and the same rated accuracy of roughly -20 to +40 seconds per day out of the box.
Do NH35 and NH36 use the same hands?
Yes. Both use standard NH-series hand fittings of 1.50mm hour, 0.88mm minute, and 0.20mm seconds, so any NH-compatible hand set will fit either.