If you've spent any time shopping for a watch — especially a Seiko mod — you've probably run into terms like "automatic," "quartz," and "hybrid" without much explanation of what they actually mean. And honestly, that's a fair thing to be confused about. These terms get thrown around like everyone already knows, when most people just want to know: does it matter, and which one should I get?
Short answer: yes, it matters — but not in a complicated way once it's broken down.
Here's the full picture.
What Is a Quartz Movement?
A quartz movement runs on a battery. Inside, a small quartz crystal vibrates at a precise, constant frequency when an electrical current passes through it — exactly 32,768 times per second, if you're curious. That vibration is converted into the steady "tick" that moves the watch hands forward, one second at a time.
The result: quartz watches are extremely accurate — typically within a few seconds per month — low-maintenance, and affordable to produce. The trade-off is that the battery eventually runs out and needs replacing, usually every 1-3 years.
Most everyday watches — the kind you'd find at a department store — use quartz movements. They're reliable, simple, and "just work."
What Is an Automatic Movement?
An automatic movement is mechanical — no battery, no electricity. Instead, it runs on a tightly wound mainspring that slowly releases energy to power the watch's gears and hands.
Here's the part that makes automatics genuinely clever: a weighted rotor inside the watch spins freely as your wrist moves throughout the day. That motion winds the mainspring automatically — hence the name "automatic." As long as you wear the watch regularly, it never needs winding by hand and never needs a battery.
The result: automatic watches have a small mechanical "heartbeat" — the seconds hand sweeps smoothly rather than ticking, and if you listen closely, you can hear the faint sound of the movement working. They're slightly less accurate than quartz (typically a few seconds per day, not per month), but for most people, that difference is barely noticeable in daily life.
This is the appeal that draws a lot of people into mechanical watches in the first place — there's something satisfying about wearing a tiny, self-sustaining machine that's been doing essentially the same thing, the same way, for centuries.
What's a Hybrid (Mecha-Quartz) Movement?
There's a third category worth knowing about, especially if you're shopping for a chronograph: hybrid movements, sometimes called "mecha-quartz."
These run on a battery like a standard quartz movement — so they're accurate and low-maintenance — but they're paired with mechanical components that control the chronograph functions (the stopwatch subdials and pushers). The result is a chronograph that feels mechanical when you use it — satisfying pusher resistance, an instant "snap" when you start or stop the timer — while still keeping the simplicity and accuracy of quartz for everyday timekeeping.
It's a "best of both" approach, and it's a big reason hybrid movements are popular in chronograph-style watches at accessible price points.
Real Examples: Movements You'll See in Seiko Mod Watches
Here's where this gets practical. If you've been browsing Seiko mod watches, you've likely already seen these movement names without necessarily knowing what they meant.
Seiko NH35 — Automatic
The most common automatic movement in the Seiko mod world, and for good reason. It's reliable, widely available, easy to service, and has earned a reputation as a genuine workhorse. If a watch lists "NH35," it's a no-date or date-display automatic — self-winding, no battery, smooth sweeping seconds hand.
Example: Seiko Mod Datejust Wimbledon — A clean, everyday automatic build powered by the NH35, paired with the textured Wimbledon dial. It's the movement at its most versatile — reliable enough to wear daily, refined enough for a dress watch.
Seiko NH34 — Automatic (GMT)
Built on the same foundation as the NH35, but with an added GMT function — a fourth hand that tracks a second time zone against a 24-hour bezel. Still fully automatic and self-winding, just with one extra genuinely useful feature for travelers.
Example: GMT Batman — The NH34 powers the GMT hand against the black-and-blue ceramic 24-hour bezel here, giving the watch genuine second-time-zone function alongside its self-winding automatic core.
Seiko NH38 — Automatic (No-Date)
Functionally similar to the NH35, but without a date window — which means a cleaner, more symmetrical dial. A good choice for designs like open-heart skeleton dials, where an uninterrupted dial layout matters visually.
Example: Nautilus Rose Gold Open Heart — The NH38's no-date layout keeps the dial clean and balanced, which matters here since part of the movement itself is visible through the open heart aperture.
Seiko NH72 — Automatic (Skeleton)
An automatic movement specifically designed to be seen. It's decorated and finished to look good through an open or skeletonized dial, with a visible rotor and gear train in motion. Same self-winding mechanics as the NH35 family, built for watches where the movement itself is part of the appeal.
Example: Seiko Mod Royal Oak Midnight Skeleton — The NH72's open architecture and decorated rotor are fully visible through the skeleton dial, turning the act of checking the time into a small mechanical show.
Miyota 8285 — Automatic (Day-Date)
A Japanese automatic movement known for its smooth-sweeping seconds hand and reliable day-and-date display. A well-regarded alternative to Seiko's own calibers, often used in dress watch builds.
Example: Seiko Mod Day-Date Gold Roman Green — The Miyota 8285 powers the fully functional day and date display here, paired with a gold-finished case and Roman numeral dial for a dress watch feel.
Seiko VK63 — Quartz (Chronograph)
The hybrid option. Runs on a battery for accurate everyday timekeeping, but the chronograph subdials and pushers operate mechanically — giving that satisfying "click" and instant response when you start, stop, or reset the stopwatch.
Example: Seiko Mod Daytona Panda — This is the VK63 in action. The black-and-white "Panda" dial features fully functional chronograph subdials powered by the VK63, paired with a 316L stainless steel case and sapphire crystal. It's the clearest example in the collection of what a hybrid mecha-quartz movement actually feels like to use — quartz-accurate timekeeping with genuine mechanical chronograph function.
So Which One Should You Choose?
It really comes down to what you value in the experience of wearing a watch.
Choose Automatic (NH35, NH34, NH38, NH72, Miyota 8285) if:
- You like the idea of a self-winding mechanical watch with no battery to replace
- You wear your watch daily or near-daily (automatics need regular wrist time to stay wound)
- You appreciate the smooth sweeping seconds hand and the small mechanical "heartbeat"
- You want a classic GMT, dress watch, or everyday build
Choose Quartz (VK63) if:
- You want a chronograph with real mechanical feel in the pushers and subdials
- You want the accuracy and low maintenance of quartz, without sacrificing that tactile experience
- You're drawn to Daytona or chronograph-style designs
There's no wrong answer here — both are genuinely good. It's less about which is "better" and more about which experience you're looking for on your wrist.
The Bottom Line
- Quartz movements are accurate, low-maintenance, and battery-powered.
- Automatic movements are mechanical, self-winding, and carry that small satisfying "alive" quality that draws people into watches in the first place.
- Hybrid mecha-quartz movements combine the accuracy of quartz with the tactile feel of mechanical chronograph function.
Every Seiko mod watch lists its movement clearly for exactly this reason — so you know precisely what's powering the watch on your wrist, and can choose the one that fits how you actually want to experience it.
Choosing the right watch is ultimately about more than just specifications—it’s about finding a piece that fits seamlessly into your daily life. The best watches are the ones you don’t have to think twice about—reliable, versatile, and naturally aligned with your personal style.
At Watches By Cody, our goal is simple: to offer watches that combine timeless design, dependable performance, and real-world wearability—without the unnecessary markup often found in traditional luxury retail. We focus on pieces that look refined, feel right on the wrist, and hold up over time.
If you’re ready to find a watch that fits both your style and your lifestyle, explore our latest collection at Watches By Cody and discover the piece that works for you.
