Movements
NH35 vs 4R35
The most-argued question in entry-level mechanical watches, and it has a short answer.
By Stephen V. · Updated Jul 24, 2026
They are the same movement. Seiko Instruments manufactures it, sells it to third-party watch companies as the NH35, and supplies it to Seiko’s own watch division as the 4R35. The architecture, dimensions, beat rate, power reserve and jewel count are identical. What differs is the stated regulation tolerance and the sales channel.
Side by side
| NH35 | Seiko 4R35 | |
|---|---|---|
| Manufacturer | Seiko Instruments | Seiko Instruments |
| Beat rate | 21,600 vph | 21,600 vph |
| Jewels | 24 | 23 |
| Power reserve | 41 h | 41 h |
| Diameter | 27.4 mm | 27.4 mm |
| Hacking | Yes | Yes |
| Hand-winding | Yes | Yes |
| Stated accuracy | Wider published tolerance | -35 to +45 sec/day |
| Sold to | Third-party watch brands | Seiko's own watch division |
The jewel-count difference in the table is a documentation quirk rather than a construction one — the figure Seiko publishes for its own 4R35 counts differently from the figure Seiko Instruments publishes for the externally sold NH35. It does not indicate a different part inside.
What this means if you are buying
A microbrand watch with an NH35 is not running a lesser movement
This is the useful conclusion. If you are weighing a microbrand watch against a Seiko and the movement is the sticking point, it should not be. What you get from Seiko is the case, the dial, the regulation, the warranty and a service network — all of which are worth money, none of which is the engine.
Regulation is real but small
Seiko regulates its own watches to a published window; a microbrand may or may not regulate the movements it buys in. In practice individual examples of both vary more than the published tolerances suggest, and either can be regulated by a watchmaker for a modest fee.
Service is where the difference bites
A Seiko can be serviced by Seiko. An NH35 in a microbrand case is serviced by an independent watchmaker, which is generally fine and occasionally awkward if the brand has gone quiet and you need a specific part. That is a genuine consideration and it has nothing to do with movement quality.
What we have not done
We have not opened, timed or compared examples of either movement. Everything above is from published manufacturer documentation. If you want measured amplitude or rate figures, this is not the page for them and we are not going to invent any.
The watches on this page
Specifications are transcribed from Seiko’s published documentation. Prices come from Amazon and carry the date they were verified. We have not handled these watches — here is what we did instead.
Price as of Jul 24, 2026. Prices move — Amazon's is the one that counts.
#ad · we may earn a commission from this link to Seiko 5 Sports SRPD65
Seiko 5 Sports SRPD65
SRPD65K1Best for: A first mechanical watch you will not outgrow
The SKX case with a movement that hacks and hand-winds. The default answer under $350, and the one most people should stop looking after.
- Spec completeness for the price
- 8.8
- Movement relative to bracket
- 8.5
- Case proportions
- 8.9
- Strap flexibility
- 9.5
- Availability
- 9.0
What it gets right
- Hacks and hand-winds — the SKX's biggest omission, fixed
- 22 mm lugs put the entire aftermarket strap catalog in play
- Day-date in a genuinely legible layout
- Case shape is the SKX profile people actually want
What it gets wrong
- Hardlex, not sapphire — it will scratch
- 100 m and no screw-down crown, so it is not an ISO 6425 diver despite the looks
- 13.4 mm thick under a shirt cuff
Skip this one if: you want an actual dive watch. The 100 m rating and the absence of a screw-down crown mean this is a dive-styled sports watch, not an ISO 6425 diver. The Turtle is the real one.
| Case diameter | 42.5 mm |
|---|---|
| Lug-to-lug | 46.0 mm |
| Thickness | 13.4 mm |
| Lug width | 22 mm |
| Crystal | Hardlex (hardened mineral) |
| Water resistance | 100 m — splash and swim, not scuba |
| Bezel | Unidirectional, 120-click |
| Lume | LumiBrite |
| Caliber | Seiko 4R36 |
| Type | Automatic, hand-winding and hacking |
| Beat rate | 21,600 vph (6 beats/sec) |
| Jewels | 24 |
| Power reserve | Approx. 41 hours |
| Stated accuracy | -35 to +45 sec/day |
| Complications | Day and date |
$525.0016% off
Price as of Jul 24, 2026. Prices move — Amazon's is the one that counts.
#ad · we may earn a commission from this link to Seiko Prospex Samurai SRPF03
Seiko Prospex Samurai SRPF03
SRPF03K1Best for: A 200 m diver with sharp, faceted case geometry
The angular one. A 200 m ISO diver with hard-cut case facets — the Seiko diver you buy when the Turtle is too round.
- Spec completeness for the price
- 8.8
- Movement relative to bracket
- 8.4
- Case proportions
- 8.6
- Strap flexibility
- 9.5
- Availability
- 8.3
What it gets right
- Slimmer than the Turtle at 12.8 mm
- Faceted case catches light in a way the rounder Seikos do not
- Full ISO 6425 diver rating
What it gets wrong
- Date only — no day, unlike the 4R36 references
- Hardlex
- Sharp lug edges are less forgiving on a small wrist
Skip this one if: you want the day complication. The Samurai runs the 4R35, which is the same movement as the 4R36 minus the day wheel.
| Case diameter | 43.8 mm |
|---|---|
| Lug-to-lug | 47.0 mm |
| Thickness | 12.8 mm |
| Lug width | 22 mm |
| Crystal | Hardlex (hardened mineral) |
| Water resistance | 200 m, ISO 6425 rated |
| Crown | Screw-down |
| Caliber | Seiko 4R35 |
| Type | Automatic, hand-winding and hacking |
| Beat rate | 21,600 vph (6 beats/sec) |
| Jewels | 23 |
| Power reserve | Approx. 41 hours |
| Stated accuracy | -35 to +45 sec/day |
| Complications | Date |
Questions
Is the NH35 the same as the 4R35?
Yes, architecturally — same manufacturer, same dimensions, same beat rate, reserve and construction. The difference is the stated regulation tolerance and which division sells it.
Is a Seiko with a 4R35 better than a microbrand with an NH35?
Not because of the movement. Seiko gives you regulation, warranty and a service network; a microbrand may give you a better case or crystal for the money. Decide on those, not on the caliber.
Why does Seiko sell the same movement under two names?
Seiko Instruments is a separate division that sells movements as a component business. The NH designation is its external product name; 4R is the name Seiko’s watch division uses internally.
Which is more accurate, NH35 or 4R35?
The 4R35 carries a tighter published tolerance because Seiko regulates its own watches. Individual examples of both vary more than that difference, and either can be regulated further.
Sources
- Seiko Instruments — movement division (NH-series manufacturer)
- Seiko Watch Corporation — US catalog and specifications
- Seiko instruction manuals and caliber documentation
Specifications are transcribed from manufacturer documentation and published standards. Where a manufacturer does not publish a figure, this page says so rather than estimating one.
Read next
- NH35 movement referenceThe full specification and what uses it.
- Seiko 4R35 caliber referenceThe Seiko-side version, with the watches it sits in.
- Seiko 4R36 caliber referenceThe day-date sibling, and Seiko's most common movement.
- Seiko Prospex vs Orient KamasuWhere the NH-series aftermarket matters to a buying decision.