The History of the Seiko NH35 and NH34 Movements:
- Militex Watches
- Jun 2
- 4 min read
Reliability, Popularity and Ease of Service.
When it comes to automatic watch movements, few calibres have earned the reputation and widespread adoption of the Seiko NH35 and NH34. Found in thousands of watches from independent microbrands to established manufacturers, these movements have become the benchmark for reliability, durability, and value.
At Militex Watches, we choose movements that deliver proven real-world performance. The NH35 and NH34 represent exactly that philosophy—dependable engineering backed by decades of Seiko expertise.
The Origins of the NH35
The NH35A is manufactured by Time Module Inc. (TMI), a subsidiary of the Seiko Group. It is essentially the commercial version of Seiko's well-known 4R35 movement, which is used in many Seiko-branded watches. The movement traces its heritage to the legendary Seiko 7S26 calibre, renowned for its durability and longevity. The NH35 improved upon this foundation by introducing two highly requested features: manual winding and hacking seconds.
Introduced to the wider market in the early 2010s, the NH35 quickly became the preferred movement for watch manufacturers seeking a robust and affordable automatic calibre. Its combination of reliability, availability, and straightforward construction helped it become one of the most widely used mechanical movements in the world.
The Arrival of the NH34 GMT
In 2022, Seiko expanded the NH family with the launch of the NH34A. Based on the proven architecture of the NH35, the NH34 added a GMT complication, allowing the wearer to track a second time zone using an independently adjustable 24-hour hand.
Before the NH34 arrived, affordable automatic GMT watches were relatively rare. GMT complications were typically found in significantly more expensive Swiss or premium Japanese movements. The introduction of the NH34 changed the landscape, giving microbrands and enthusiasts access to a dependable mechanical GMT movement at an accessible price point.
Today, the NH34 powers a huge number of GMT watches across the industry and is widely regarded as one of the most important developments in affordable watchmaking in recent years.
Why Are These Movements So Popular?
The success of both the NH35 and NH34 comes down to a simple formula: reliability, practicality, and value.
Both movements feature:
Automatic self-winding operation
Manual winding capability
Hacking seconds for accurate time setting
Approximately 41 hours of power reserve
Seiko's Diashock protection system
24 jewels to reduce friction and wear
Proven long-term durability in daily use
For watch brands, these movements offer a dependable platform with excellent parts availability. For owners, they provide the confidence that comes from wearing a movement with a proven track record across millions of watches worldwide.
The NH35 has become particularly popular among dive watches, field watches, and everyday sports watches. Meanwhile, the NH34 has become the movement of choice for affordable GMT watches, enabling travellers and professionals to track multiple time zones without paying luxury watch prices.
Reliability That Has Earned a Global Reputation
One of the biggest reasons for the enduring popularity of the NH35 and NH34 is their reliability.
Unlike some highly complex movements that prioritise performance at the expense of robustness, the NH series was designed with durability in mind. The relatively simple architecture, combined with decades of Seiko engineering experience, has resulted in movements capable of running reliably for many years with routine maintenance.
The official accuracy specification of approximately -20 to +40 seconds per day may appear modest on paper, but many examples perform significantly better once regulated. More importantly, these movements are designed to continue performing consistently under everyday conditions rather than chasing laboratory-level precision.
For military-inspired, aviation, and tool watches, reliability is often more important than absolute accuracy. A dependable movement that continues to function year after year is precisely what many enthusiasts value most.
Ease of Service and Long-Term Ownership
Another major advantage of the NH35 and NH34 is how easy they are to service.
Because these movements are used by countless manufacturers around the world, replacement parts are widely available. Most professional watchmakers are familiar with the NH family, making routine servicing straightforward and cost-effective.
In some cases, replacing an NH35 movement can be more economical than performing a complete overhaul on a more expensive calibre. This practical approach has made the movement particularly attractive to microbrands and enthusiasts who prioritise long-term ownership costs.
The NH34 shares much of its architecture with the NH35, meaning it benefits from the same serviceability while adding the useful GMT function. For owners, this means the convenience of a second time zone without significantly increasing maintenance complexity.
Why Militex Chooses the NH Series
At Militex Watches, we believe a watch movement should inspire confidence. While there are many calibres available today, few have earned the trust and reputation of the Seiko NH35 and NH34.
These movements combine proven reliability, practical features, global serviceability, and exceptional value. Whether powering a rugged field watch, a dive watch, or a GMT designed for travel, they deliver the dependable performance that enthusiasts have come to expect from Seiko engineering.
That is why the NH35 and NH34 remain among the most respected automatic movements in modern watchmaking—and why they continue to power watches that are built to be worn, used, and relied upon every day.
