The BEST Movement for Seiko Modding?

A watch’s movement is its beating heart, and in the case of Seiko's NH series, these hearts are robust, reliable, and revered. Known for their automatic winding mechanisms and precision, these movements have become the go-to choice for watch modders worldwide. The NH series balances traditional watchmaking craftsmanship with modern technological advances, offering a range of functionalities to suit various modding needs. 

If you're new to Seiko modding, it might be tough to decide which movement is going to work best for your watch build, so hopefully this blog post helps point you in the right direction.

 

Seiko NH35: The Workhorse

This is hands down one of the most popular movements used in Seiko modding. Affordable, reliable, versatile - It's not hard to understand why it's the reigning champion.

At the heart of the NH35's appeal is its robustness. As an automatic movement, it is powered by the natural motion of the wearer’s wrist, eliminating the need for manual winding or frequent battery replacements. This feature is particularly attractive to modders who value both practicality and the classic charm of mechanical movements. The NH35 is also known for its accuracy and dependability, traits that Seiko has perfected over decades of watchmaking expertise.

Another critical factor in the NH35's popularity among modders is its versatility. The movement is designed to be straightforward to work with, making it an ideal choice for those who are just dipping their toes into the intricate world of watch modding. Its compatibility with a wide range of cases and dials means that it can be used to create an array of watch styles, from sleek and modern designs to more traditional or rugged looks.

The NH35 also features a date function, adding a layer of functionality to the watches it powers. This complication is easily integrated into various dial designs, providing modders with the flexibility to create both aesthetically pleasing and practical timepieces. Additionally, the NH35's hacking mechanism, which stops the second hand while setting the time, allows for greater precision – a feature often sought after by watch enthusiasts.

In terms of customization, the NH35’s unbranded nature is a significant advantage. It allows modders to create unique, personalized watches without the constraints of brand-specific design elements. This freedom is a key driver behind the NH35’s widespread use in custom watch projects.

The Seiko NH35 is a foundational element in the world of watch modding due to its reliability, user-friendly nature, and versatility. It provides an excellent base for a wide variety of modding projects, appealing to enthusiasts who value both function and form in their customized timepieces.

Decided to go with the Seiko NH35? You can go with either our White Datewheel NH35 or our Black Datewheel NH35 - yes, even the colour of the datewheel matters when choosing a movement for your watch build.

 

Seiko NH36: Date AND Day Functionality

A defining feature of the NH36 is its day-date complication. Unlike the NH35, which only displays the date, the NH36 adds a day function, providing added utility and an extra layer of interest on the watch's face. This feature enhances the appeal of the movement for modders who aim to craft timepieces that are not just visually striking but also highly functional. The day-date complication is seamlessly integrated into the movement, allowing for a wide range of creative dial designs and layouts.

Like the NH35, the NH36 boasts the durability and precision synonymous with Seiko's craftsmanship. Its automatic winding mechanism, powered by the motion of the wearer's wrist, ensures a constant and reliable power supply, making the watch both practical and low maintenance. The NH36 also includes a hacking feature, allowing for precise time-setting – a much-appreciated detail by watch enthusiasts.

The NH36's adaptability to various styles and designs makes it a versatile choice for modding. From elegant dress watches to rugged, adventurous designs, the movement provides a solid foundation that can be tailored to fit a myriad of aesthetic preferences. Its reliability and added functionalities make the NH36 a sought-after movement for modders who wish to elevate their custom watch projects with a touch of sophistication and enhanced practicality.

Think your watch build needs a day and date function? Get a Seiko NH36 here. If you prefer the Day/Datewheel to be black - and if you want the Day to be in Kanji to pay homage to Seiko's Japanese origins, this NH36 with a Black Kanji Datewheel is the one for you.

Seiko NH38: Date-Free and Open-Hearted

The Seiko NH38 offers a clean, minimalist approach to automatic movements. Unlike its siblings in the NH series, the NH38 doesn't include a date function, making it perfect for modders who prefer a simpler, uncluttered dial design. This streamlined approach allows for more creative freedom when designing watch faces, as there's no need to accommodate a date window.

Thanks to the absence of a date complication, it eliminates the “ghost date” problem where you feel a phantom click in crown operation despite no date display.

What makes the NH38 stand out is not only its focus on pure timekeeping but also its flashiness that allows you to showcase the movement itself. At the 9 o’clock position, Seiko engineered the NH38 with exposed parts of the balance wheel and escapement, the components responsible for regulating time. This makes the NH38 ideal for “open-heart” dials, where a cutout on the dial reveals the rhythmic oscillation of the movement. Perhaps not as seductive as a full on skeleton movement, but an intriguing feature nonetheless.

Here's an article diving deeper into open-heart Seiko modding, particularly with a Nautilus-inspired case.

The NH38 still carries all the hallmarks of the NH family: automatic winding powered by wrist movement, hacking for precise time setting, and a sturdy build that ensures long-term reliability.  

 

Seiko NH34: The Master of GMT

The Seiko NH34 movement is especially prized in watch modding for its GMT (Greenwich Mean Time) capability, which enables the tracking of an additional time zone. This feature is not just a technical advancement but also a nod to the spirit of adventure and global connectivity, making it a coveted choice for enthusiasts creating international travel-themed or professional timepieces. 

Unique among its siblings in the NH series, the NH34 allows modders to incorporate a level of complexity and utility typically reserved for high-end watches. The movement's ability to display a second time zone is not just functional but also adds an element of intrigue and sophistication to the watch's face. This feature is particularly appealing for modders looking to craft timepieces that are both conversation starters and practical tools for frequent travelers or professionals with global connections.

 

 

In terms of reliability and construction, the NH34 maintains the high standards set by Seiko's NH series. It features automatic winding, ensuring that the watch stays powered through the wearer's natural motion, thus offering the convenience of not requiring manual winding or frequent battery changes. The inclusion of a hacking mechanism also means that time can be set with precision, a detail highly valued by watch enthusiasts and collectors alike.

The NH34's versatility in design integration makes it suitable for various watch styles, from sleek and modern to more traditional designs. Its added functionality does not compromise its ease of use in modding, making it accessible to both experienced modders and those new to the craft.

Ready to build a watch that's destined for globetrotting? Get your Seiko NH34 here.

And if you need even more info on the NH34, check out our Ultimate NH34 Guide here.

 

Seiko NH70/71 - True Beauty Lies Within

The NH70/71 stands out with its open-heart design, a feature that allows a glimpse into the rhythmic dance of the watch's internals. This design choice is not just a showcase of mechanical beauty but also serves as a bridge between traditional watchmaking and contemporary design sensibilities. The movement's skeletal nature transforms the watch face into a dynamic canvas, revealing the intricate workings typically hidden beneath the dial. The NH70/71 is particularly appealing for modders aiming to craft watches that are not just timekeeping tools but conversation pieces that exhibit the artistry of mechanical movements.

Just answer this question - do you want something that's a bit more of a visual spectacle? Then yes, the Seiko NH70 and Seiko NH71 might be the movement of choice for you.

Here's an in-depth guide if you want to dive deeper into Skeleton mods.

 

Are There Fake NH Movements?

When you’re starting a Seiko mod, one of the first questions that comes up is: are NH movements ever faked? The good news: not really. NH movements like the NH35 and NH36 are affordable, reliable, and mass-produced, which means counterfeiters have no reason to bother copying them. That’s why they’ve become the go-to choice for beginners and veteran modders alike.

But that doesn’t mean fake movements don’t exist. High-end calibers from ETA or Sellita are often counterfeited, and using one in your build can mean poor reliability and wasted money.

Want the full scoop, including how to spot fakes and the truth about SII and TMI branding? Check out the full article here.

 

Having a Unique NH Movement

NH movements are not exactly flashy. Unless you’re using one of the skeletonized NH7X series, most NH calibers are built more for function than looks. For the most part, that's perfectly fine, but that doesn’t mean they have to stay plain though. A rotor swap can instantly change the looks of your watch from the back. The rotor is the semi-circular weight that powers your watch as you wear it. By replacing the stock version with a custom design, you can transform your movement into something worth showing off through a display caseback. It’s a small upgrade that makes your build more personal and stylish.

Learn more about swapping the NH stock rotor to a better-looking one in this article.

 

Quartz Movements for Modding

When it comes to Seiko modding, quartz movements rarely get the spotlight. Most builders reach for the NH35 or other automatics, leaving quartz largely ignored. But quartz actually has a lot to offer for adventurous modders.

Quartz movements work by sending an electrical charge through a tiny crystal that vibrates at a precise frequency. The result is a very impressive accuracy of within 15 seconds per month, compared to 15 seconds per day for some mechanical movements. They’re also affordable, reliable, and low-maintenance, making them perfect for those who want a no-fuss daily watch.

There are downsides, of course. Some enthusiasts say quartz lacks the “soul” of a mechanical watch. Batteries also add waste and can hurt water resistance when replaced. And since quartz movements are simpler, there’s less tinkering involved for hobbyists who enjoy servicing their own builds.

Still, quartz movements open up creative possibilities. They allow complications like alarms, calendars, and chronographs at a fraction of the cost of mechanical equivalents. Their thinner profiles also free up case space, giving modders more room to play with crystals, bezels, or casebacks.

 

Quartz Chronographs You Can Mod With Today

If you're willing to try out Seiko Quartz modding, here's a family worth considering: the Seiko VK mecha-quartz chronograph movements. These hybrids combine quartz accuracy with a mechanical-style chronograph sweep so you can bring those Seiko Panda and Carrera Skipper Seiko mod dreams to life.

Each VK calibre brings something different to the table:

• VK64 – A bi-compax layout with 60-minute chrono counter and 24-hour subdial, plus a date at 6. Clean, vintage-inspired, and perfect for minimal builds.

• VK63 – A tri-compax layout with small seconds at 6, chrono counter at 9, and 24-hour subdial at 3. Popular for racing-style mods or Daytona-inspired builds.

• VK67 – Adds a 12-hour counter, making it a true tool chronograph for tracking long intervals.

• VK61 – Symmetrical layout with chrono at 12, running seconds at 6, and date at 3. Simple, balanced, and budget-friendly.

Compared to bulky and pricey mechanical chronographs, VKs are thinner, easier to build with, and far more accurate (±15 seconds per month). For modders who want the chronograph look without the headaches, they’re a game-changer and are perfect to use with our Chrono cases.

Learn more about VK Chronograph Movements here.

 

Beyond Seiko: Miyota Movements

While Seiko’s NH family is the backbone of the modding world, they aren’t the only Japanese movements worth paying attention to. Miyota, owned by Citizen, has built a strong reputation for producing affordable (compared to Swiss counterparts) yet reliable calibers. Two of their standouts, the 9015 and 90S5, are reshaping what’s possible for modders and microbrands alike.

The Miyota 9015, launched in 2009, quickly became a favorite among watch startups thanks to its blend of performance and price. Beating at a higher 28,800 vibrations per hour (compared to the NH35’s 21,600), it delivers a smoother seconds hand and greater accuracy (-10 to +30 seconds per day). Its thin 3.9mm profile also opens the door to slimmer case designs, something NH movements often limit. Add a 42+ hour power reserve, hacking seconds, and bidirectional winding, and you’ve got a proven workhorse that rivals Swiss options like the ETA 2824 at a fraction of the cost.

Building on that success, Miyota introduced the 90S5 in 2020. Essentially a refined 9015, it adds improved shock resistance, redesigned internals for better performance, and an “open-heart” balance wheel at the bottom area that’s perfect for skeleton builds. 

Compared to Seiko’s NH70/NH71 open-heart movements, the 90S5 stands out for being thinner, faster, and more precise. While availability is still limited, its potential for modding is clear, especially with aftermarket support now arriving.

Miyota calibers may not be dethroning the NH series anytime soon, but they're an exciting alternative for modders seeking slimmer cases, smoother sweeps, and a more premium-feeling movement. Check out our Miyota-compatible parts here.

 

So... What's the best Seiko movement for modding?

The idea of a "best movement" in watch modding is more of a catchy, clickbait title than a reality. Truthfully, there's no one-size-fits-all 'best' movement. What matters most is finding the 'best' movement for your specific project and needs.

Each movement serves a particular purpose in modding. Their individual features make them suitable for different types of watches and modding goals and choosing the right movement depends on what you’re trying to achieve. Are you after functionality, aesthetic appeal, or a blend of both?

The 'best' movement is the one that aligns with your personal preferences, the specific requirements of your modding project, and the functionality you want in your customized watch.

It's not about flashy titles or generalizations; it’s about matching the right tools to the task at hand and achieving the desired outcome in your watch modding venture. Pick your poison!