Seiko SII Caliber NH35

Seiko (SII) Caliber NH35A

Seiko SII Caliber NH35

ManufacturerSeiko
Caliber NumberNH35A (aka NH35)
Movement TypeAutomatic
Jewels24
Vibrations Per Hour
21,600 bph
Lift Angle53 degrees
Shock SystemDiashock
Power Reserve
41 hours
Winding Direction
Bi-directional (Magic Lever)
Hacking?Yes
Hand-Windable?Yes
Diameter27.40mm (outside) / 29.36mm (casing)
Height5.32mm
FunctionsHours, minutes, central seconds, date calendar
Country of ManufactureJapan/Malaysia
Known Brands
Seiko, Invicta, Vostok, Lum-Tec, Spinnaker, Minus-8 Layer, Advisor AstroHelm, Advisor Ascent (add more in the comments below)

The Seiko/TMI/SII caliber NH35A is a hand-windable, hacking upgrade from the Seiko caliber NH25A (read more here). The earliest documentation on this movement that we were able to find was issued on 2/14/2011, this also corresponds with the 2011-2012 time frame that the first NH35A powered watches started hitting the market.

The NH35A is currently one of the world’s most popular automatic movements and is widely available in many affordable/microbrand watches.

Time Module aka Seiko Instruments labels the NH calibers as part of the “Basic” Mechanical Series. They also have NE calibers that are labeled as “Premium” Mechanical Series.

NH35A Also Known As…

It’s also important to note that the Seiko NH35A movement is basically an unbranded version of the Seiko caliber 4R35. for example, the NH36 is an unbranded version of the 4R36 (day + date) found in the Next Generation Orange Monster. More information here.

Accuracy:

In the technical documentation, Time Module claims that the NH35A accuracy range is within -20~+40 seconds per day under normal conditions. They recorded these accuracy measurements without the date complication being active. This shouldn’t have any noticeable bearing on the accuracy, but it’s interesting nonetheless.

Note: When you attempt to get a measurement of your watch’s accuracy, it’s important to make sure your watch is fully wound or the lack of power reserve may skew the test results. TMI states that measurements should be done within 10-60 minutes after the movement is fully wound up.

Winding the Mainspring:

So what does fully wound up mean? The NH35A should be fully wound after about 55 manual turns of the crown.

This movement is also equipped with the Seiko Magic Lever, so shaking the watch side to side should get it going almost immediately.

Crown Position Functions:

0 (against the case): Clockwise = Manual Winding / Counterclockwise = Nothing
1 (pulled out one click): Clockwise = nothing / Counterclockwise = Date setting
2 (pulled out two clicks): Time setting clockwise and counterclockwise

Rotor Variations

While many watch brands that use the NH35A will opt for a custom rotor (oscillating weight), as of the official tech sheets from March 2017, two stock rotors are available depending on the country of origin: Japan or Malaysia.

Sii Caliber Nh35a Rotor Japan Malaysia

Replacement Price

At the time of this post, replacement prices for the caliber NH35A were found online for around $46.00 USD. Buy it here


Examples of NH35A Powered Watches

Seiko NH35A movement in a Minus-8 Layer watch

NH35A in a Vostok Jurgis Kairys – notice that this one doesn’t say Japan or Malaysia on the top.

NH35A in a BOLDR Odyssey bronze meteorite dial diver found here.

Sii Nh35a Boldr Micro Brand Dive Watch

Video Action:

Here is a quick film of an NH35A movement found in a BOLDR Odyssey bronze microbrand dive watch.


Additional Resources:

You are reading Caliber Corner, the most popular resource for watch movement pics, specs and opinions, including mods and DIY repairs. CC is a watch geek community for gear turning and caliber learning! Check the front page for the latest caliber listings and follow Caliber Corner on Twitter, Instagram and Facebook. Subscribe to our YouTube channel for close-up movement videos. Join our mission to spread movement awareness. Sign up!
What do you think about Seiko (SII) Caliber NH35A? Keep comments respectful and follow our community guidelines.
Subscribe
Notify of
guest
320 Comments
Inline Feedbacks
View all comments
Graham Cracker
Graham Cracker
4 months ago

I am wondering about rotor noise with the NH35A watches. I had a Miyota that had slight noise. It didn’t bother me but I read people complaining about it a lot. What I don’t see is people complaining about the Seiko having rotor noise. If you were to compare the two, is NH35A so much quieter?? I did a comment search before posting this but please forgive me if this has been discussed already. Thank… Read more »

Mark Madeley
Mark Madeley
2 months ago
Reply to  Graham Cracker

No rotor noise is noticeable to me. The Miyota 82xx movement is very loud in my experience. I somewhat prefer the Chinese clone DG2813 over the Miyota because of the noise although the Miyota is a better build. For the Seiko, I don’t get the sense the rotor is freewheeling as much. If it is bidirectional winding, then that might explain it. Good question. You have your Miyota vs Seiko guys/gals and that’s about the… Read more »

Jorge Robles
Jorge Robles
1 month ago
Reply to  Graham Cracker

You are concerned about the noise of the rotor as it turns around? And who is this people you are talking about? And Why? Is there any rattling or cracking noise? If not, then do not be worry. I have never heard anything about it, and I am amateur watchmaker and give service to many of these NH35’s just for regular CLA, and they are for sure workhorses, way better than the 7s26/36 they replaced.… Read more »

DC
DC
7 days ago
Reply to  Graham Cracker

you can hear it if you put your ear up to it, but if it is at an arms length away, it is not noticeable. i actually enjoy having the little tick there if i want to put my ear up to it and listen.

trackback
New Watch Alert 5/8/2020 - The Truth About Watches
4 months ago

[…] coated gunmetal case (for the Kryptonian Battle Armor look) and meteorite effect dial. It runs on a Seiko NH35A automatic movement. NOTE: If you buy this watch and you’re older than 12, sell those comic […]

Adrian G
Adrian G
3 months ago

Also on Dapix Carpathica is used

Randy Dunning
Randy Dunning
3 months ago

Have a Maratac (X1) SR-35 Titanium Diver with this action. Very nice watch. It is nice to be back in a self winder after years of fussing with battery watches.

Michael
Michael
3 months ago

Also in the fabulous SteelDive 1970 and SteelDive 1940 watches.

Titus Aquino
Titus Aquino
2 months ago

Hi there, is it normal that my watch with nh35a advances an average of 24 seconds a day? Thanks

johnnyjohnny
johnnyjohnny
2 months ago
Reply to  Titus Aquino

technically your watch is just slightly out of the manufacturer’s specs for this movement, which is -20 sec day. you should be sure it’s wound and/or worn enough to keep good power in it, and if it is, you would probably just need to have it adjusted by a watchmaker. you do not mention how old it is or when the last servicing was. it could be that it is in need of servicing. or,… Read more »

AZ
AZ
2 months ago
Reply to  Titus Aquino

Reread the accuracy section above. Other than that, everything @johnnyjohnny said is on point

trackback
Collins Sonar – Beans & Bezels
2 months ago

[…] the extra dough, over the Freediver or Retrospect. For starters, I observed roughly -21 spd on the Seiko NH35 in the Freediver, whereas I’ve observed +6 spd on the Sonar after logging it’s accuracy […]

trackback
UNDONE Watches Review: Can You Craft The Ultimate Watch?
2 months ago

[…] wise, it features a beefy 43.5 mm by 16mm case, a Seiko NH35A movement with an automatic winding mechanism, a 316L stainless steel case with sapphire crystal, and 100-200 […]

Anders Forsberg
Anders Forsberg
1 month ago

I have two Pagani Design watches, both Submariner hommages model PD1639 with the NH35A movement.
Both run at +1-2 secs/day. Very satisfied so far.

trackback
Reise Resolute – Beans & Bezels
1 month ago

[…] movement is a Seiko NH35A. For the price of $299, this movement is a great choice given it’s reliability. I logged the […]

trackback
Sólás Starlight – Beans & Bezels
1 month ago

[…] guess they had expected pricing to be similar to other 3 hander movements from China – or even a Seiko NH35). This wasn’t the case – and a micro-rotor movement isn’t something anyone can make – if […]

Mauro
Mauro
1 month ago

This movement is also used by the Avian Watch Company–a US-based and veteran-owned firm. The Avian Commodore Mk2 uses the NH35A

trackback
D1 Milano Review - A closer look at the atlas | Hype & Style
25 days ago

[…] you are a watch enthusiast, the Seiko SII NH35 needs no introduction, but if you are new to the game, here is the break-down: Seiko makes watches […]

trackback
Kaal Multiverse Series – Sol – Beans & Bezels
15 days ago

[…] watch uses a Seiko NH35, and for the $369/$399 launch prices, this is more than reasonable. By now, we’re all quite […]

Steve
Steve
9 days ago

I appreciate this site as always well-done, and worthwhile. An excellent, timely resource. ( I see that last sentence. It works . . . I’ll leave it. )

trackback
Wilbur Watches 2020 Launch Edition - The Truth About Watches
3 days ago

[…] would be a Seiko NH35 retrofitted with a red “Launch” branded rotor, modified to fit the “puck” […]

trackback
Dailos Waveform – Beans & Bezels
3 days ago

[…] waveform uses a Seiko NH35. The prototype I received was smooth to operate and wasn’t scratchy like some NH35s […]

trackback
D1 Milano Review - A closer look at the atlas | Hype & Style
1 day ago

[…] vous êtes un passionné de montres, le Seiko SII NH35 n’a pas besoin d’être présenté, mais si vous êtes nouveau dans le jeu, voici le contour: […]

Ed Wood
Ed Wood
22 hours ago

I am planning to replace the NH35 movement in my current watch and searching for an NH35 with Date at 4. Most of the movements on sales are with Date at 3. What problem will I face if I try to fit the Date at 3 into my watch and what can I do to adapt it to my watch? Thanks.

trackback
New Watch Alert: 8/18/2020 - The Truth About Watches
17 hours ago

[…] white time is the right time thanks to a Seiko NH35A automatic running at 21600 bph with a 41h power reserve and hacking seconds. The accuracy […]

trackback
UNDONE Basecamp: Reloj A Medida – SaFonaGastroCrono
34 seconds ago

[…] su interior, un todo terreno NH35A impulsa el reloj, añadiendo otro toque retro acentuado con su pausado […]

320
0
Would love your thoughts, please comment.x
()
x