Short answer: the Seiko NH35 and NH36 are the same automatic movement with one difference: the NH35 shows the date, while the NH36 adds a day-of-the-week display next to the date. Both run at 21,600 vph with 24 jewels, roughly 41 hours of power reserve, hacking seconds and hand-winding. At ChronoSeasons you will find NH35-powered Bersigar watches from $285 and NH36A models from $399.
What the Seiko NH35 movement is
The NH35 is a self-winding mechanical caliber made by Seiko Instruments and sold to other watch brands, often under the TMI (Time Module) name you see in product listings. It is the "unbranded" sibling of the movement family Seiko uses in its own watches, which is why you will find it inside a huge range of independent and microbrand designs.
It earned its reputation by being simple, robust and easy for any competent watchmaker to service. It is not a luxury caliber, but it is a genuine mechanical movement with features that cheaper automatics once lacked.
Core specifications (NH35 and NH36)
- Type: automatic (self-winding), with manual winding through the crown.
- Frequency: 21,600 vibrations per hour (6 beats per second), giving a smooth but visibly stepped seconds hand.
- Jewels: 24.
- Power reserve: about 41 hours when fully wound.
- Hacking seconds: the seconds hand stops when you pull the crown, so you can set the time to the second.
- Accuracy: Seiko's published tolerance is wide, roughly −20 to +40 seconds per day. Many examples run far better than that, but it is the honest spec to plan around.
NH35 vs NH36: the only real difference
| Feature | NH35 / NH35A | NH36 / NH36A |
|---|---|---|
| Display | Hours, minutes, seconds, date | Hours, minutes, seconds, day and date |
| Frequency | 21,600 vph | 21,600 vph |
| Jewels | 24 | 24 |
| Power reserve | About 41 hours | About 41 hours |
| Hacking and hand-winding | Yes | Yes |
| Typical dial layout | Date window, usually at 3 o'clock | Day and date, either side by side at 3 o'clock or split (for example day at 12, date at 3) |
Everything that affects how the watch keeps time is shared. The NH36 simply carries an extra day disc and the parts that advance it. That means the choice comes down to the dial: do you want the day of the week on your wrist, or do you prefer the cleaner look of a date-only face?
The "A" suffix (NH35A, NH36A) marks the current production version. In practice the names with and without the A are used interchangeably, and you will see both in our listings.
Living with an NH35 or NH36
- Wind it after a break. If the watch has stopped, give the crown 20 to 30 turns in the winding position before setting it. That builds enough reserve for the rotor to take over.
- Set the date away from midnight. As with most mechanical calendars, avoid quick-setting the date (or day) while the hands sit between roughly 9 PM and 3 AM, when the change mechanism is engaged. Move the hands to 6 o'clock first, then set the calendar.
- Use hacking. Pull the crown fully out when the seconds hand reaches 12, set the minutes, and push it back in on a time signal.
- Service on condition. These movements are easy to service or replace, which keeps long-term ownership costs reasonable.
If you are still deciding between a mechanical watch and a battery one, our automatic vs quartz guide explains the trade-offs in accuracy and upkeep.
Which ChronoSeasons watches use the NH35 and NH36
All of our NH35/NH36 watches come from Bersigar. They pair the movement with sapphire crystals and 100m (10 ATM) water resistance across the range.
| Model | Movement | Case | Style | Price |
|---|---|---|---|---|
| Luxaura 1645 | NH35 | 42mm | Fluted bezel, cyclops date | from $285 |
| Luxaura Arabic Face 1645 | NH35 | 42mm | Eastern Arabic numerals | from $310 |
| Luxaura 1651 | NH35A | 40mm | Relief bezel, Jubilee or Oyster bracelet | from $320 |
| Luxaura 1639 | NH35A | 42mm | Rotating sapphire dive bezel | from $375 |
| Timecraft 1668 | NH35A | 43mm | Teak-textured dial, sapphire dive bezel | from $305 |
| Ocular 1685 | NH35A | 42mm | Wave-pattern dive dial | from $325 |
| Allegro 1673 | NH35A | 39mm | Octagonal bezel, integrated bracelet | from $399 |
| Luxaura 1783 | NH36A | 40mm | Day at 12, date at 3, fluted bezel | from $399 |
Our picks
- Bersigar Luxaura 1645 Black Edition: 42mm, NH35 (24 jewels), black sunburst dial with a fluted steel bezel and cyclops date.
- Bersigar Luxaura 1651 Silver Jubilee Edition: 40mm, NH35A, slate-grey sunburst dial on a five-link Jubilee bracelet.
- Bersigar Timecraft 1668 Silver Green: 43mm NH35A diver with a teak-textured emerald dial and a green sapphire bezel.
- Bersigar Ocular 1685 Black Wave: 42mm NH35A diver with a laser-engraved wave dial and scalloped sapphire bezel.
- Bersigar Allegro 1673 Silver Blue: 39mm integrated-bracelet sports watch, NH35A, gradient tapisserie dial.
- Bersigar Luxaura 1783 Silver Red Dial: 40mm, NH36A, with a full day aperture at 12 and date at 3.
- Bersigar Luxaura 1783 Silver Blue Roman Dial: the same NH36A day-date layout with Roman numerals.
Related Seiko-family calibers also appear in the catalog. The Bersigar Luxaura 1662 uses the NH34A, a GMT automatic, and Hemel's field watches such as the Hemel Helmsman use the Seiko YN55A automatic with hacking seconds and a 40-hour reserve. Browse more in Everyday or under $300, and check case sizes against your wrist with our watch size guide.
Questions we get
Is the NH36 better than the NH35?
Not mechanically. They share the same frequency, jewel count, power reserve and features. The NH36 only adds a day display, so pick the dial you prefer.
What is the difference between NH35 and NH35A?
The A suffix marks the current version of the caliber. The names are used interchangeably and the specifications are the same.
How long does an NH35 run off the wrist?
About 41 hours from a full wind, so a watch taken off on Friday evening will usually have stopped by Sunday.
Can I wind an NH35 by hand?
Yes. Unscrew the crown if it screws down, then turn it in its normal pushed-in position to wind. The rotor also winds it as you move.
How accurate is the Seiko NH35?
Seiko quotes roughly −20 to +40 seconds per day. Many run well inside that range, but it is not a chronometer-grade movement.
Do these watches come with a return window?
Yes. Every watch ships new and boxed, with 30-day returns on unworn watches.
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