NH35 vs Miyota 8215: Which Automatic Watch Movement Should You Buy?
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NH35 and Miyota 8215 are the two movements you'll see most often in affordable automatic watches, including several in our own range. The real-world difference is small but genuine: the NH35 (made by Seiko) has hacking seconds and slightly more jewels, while the Miyota 8215 (made by Citizen's Miyota division) is marginally thinner and just as reliable, but can't stop the seconds hand for precise time-setting. Neither is "better" outright — it depends what you're setting the watch for.
The two movements, side by side
| Spec | Seiko NH35 | Miyota 8215 |
|---|---|---|
| Manufacturer | Seiko (TMI) | Citizen (Miyota) |
| Jewels | 24 | 21 |
| Beat rate | 21,600 vph | 21,600 vph |
| Power reserve | ~41 hours | ~40+ hours |
| Hacking seconds | Yes | No |
| Hand-winding | Yes | Yes |
| Made in | Japan or Malaysia | Japan/Thailand |
What "hacking seconds" actually means, and why it's the real difference
Hacking is simple but genuinely useful: pull the crown out on a hacking movement and the seconds hand stops dead, letting you set the minute hand precisely against a time signal, then push the crown in at exactly the right moment. The NH35 has this. The Miyota 8215 doesn't — pull its crown and the seconds hand keeps sweeping, so you're setting the time to the nearest few seconds by eye rather than exactly. It's a small thing day-to-day, but it's the single feature enthusiasts bring up most often when picking between the two.
Where the NH35 pulls ahead
Beyond hacking, the NH35 has three more jewels (24 vs 21) — jewel count isn't a direct measure of quality on its own, but it does reduce friction at a few more points in the movement. It's manufactured by Seiko itself (via Seiko Instruments/TMI), which carries genuine brand pedigree in the watch world, and it's the movement you'll find in the majority of serious dive-watch homages — our own Steeldive SD1970, San Martin SN0007, and Seestern SUB300T all run it, among others.
Where the Miyota 8215 holds its own
The 8215 isn't a lesser movement, just a different set of trade-offs. It's manufactured by Citizen's Miyota division — one of the largest, most experienced movement makers in the world — and it's slightly slimmer than the NH35, which is why brands favour it in dressier, thinner cases like our Sea-Gull-style and CADISEN TI-7 pieces. It still hand-winds, still runs at the same 21,600vph beat rate, and in day-to-day reliability testing by independent reviewers, the two are consistently rated as comparable — the Miyota just asks you to set the time a little less precisely.
Worked examples, from our own stock
The Steeldive SD1970 is a genuine NH35 example — a 200m cushion-case diver with a sapphire crystal and ceramic bezel, where the hacking function is genuinely useful for setting a dive watch precisely. The Addiesdive AD2536 runs the Miyota 8215 in a similarly specced 200m diver — proof the 8215 isn't a downgrade in capability, just a different movement with one less feature. For a thinner dress case built around the same Miyota 8215, see the CADISEN TI-7 Canvas.
Being honest about accuracy
Neither manufacturer publishes a strict chronometer-style accuracy spec for these base calibres — they're built for reliability and cost, not precision timing. Community testing commonly reports both landing somewhere in the range of roughly -20 to +40 seconds a day out of the box, which is normal for this class of movement and not a fault with either one. If exact accuracy matters to you, both can be professionally regulated afterward, but that's an added service, not something either movement promises from the factory.
Frequently asked questions
Is NH35 better than Miyota 8215?
Not outright — the NH35 has hacking seconds and three more jewels, while the Miyota 8215 is slightly thinner and just as reliable. Most buyers prefer the NH35 for dive watches specifically because hacking makes precise time-setting easier.
Does the Miyota 8215 have hacking seconds?
No. Pulling the crown out doesn't stop the seconds hand on an 8215, so you set the time to the nearest few seconds rather than exactly.
Can you hand-wind a Miyota 8215?
Yes — both the NH35 and the Miyota 8215 support manual hand-winding as well as automatic (wrist-motion) winding.
Who makes the NH35 movement?
Seiko, through its movement-manufacturing arm (sometimes referred to as TMI), produces the NH35 in Japan or Malaysia depending on the batch.
Which movement is more accurate?
Neither has a guaranteed factory accuracy spec. Community testing generally finds both in a similar range day-to-day — differences come down to the individual watch rather than one movement being categorically more accurate than the other.
Facts to confirm: accuracy figures above are the commonly-cited community range from independent testing, not an official manufacturer spec — flagged here rather than stated as guaranteed, per our own honesty standard.
Related reading
If you'd rather see the NH35 in action, our Seestern SUB600T V3 review, Seestern SUB600T vs San Martin SN0007, Seestern SUB300T vs SUB600T, Steeldive SD1975 vs SD1970 and San Martin SN0007 vs SN0008 vs Water Ghost all cover watches built around it. For the Miyota 8215 side, see CADISEN TI-7 vs BERNY AMT358MS, our ADDIESDIVE buying guide, and the Pagani Design PD-1685 review. And if you want to see both movements in context across our current range, our 7 Best Automatic Watches Under $200 roundup features examples of each.
New to automatic watches? Start with What Is an Automatic Watch? How Self-Winding Movements Work for how the movement winds itself and how long it runs when you take the watch off.
