Exploring the Intricacies of Japanese Watch Movements: Miyota Caliber 8315 vs Seiko Caliber NH35A

In this comparison, we aim to provide an in-depth look at these two esteemed Japanese movements, the Miyota 8315 and the Seiko NH35A shedding light on their specifications, functionalities, and how they stack up in the current market.
Miyota 8315 Watch movement

The horological landscape is rich and varied, boasting an array of watch movements that breathe life into the timepieces cherished by enthusiasts worldwide. Among these, the Miyota Caliber 8315 and Seiko Caliber NH35A stand out, captivating the hearts of both aficionados and watchmakers with their distinctive qualities and widespread adoption by boutique brands like Borealis Watch Company.

In this comparison, we aim to provide an in-depth look at these two esteemed Japanese movements, shedding light on their specifications, functionalities, and how they stack up in the current market.

Miyota Caliber 8315

Crafted by Miyota, a subsidiary of the acclaimed Citizen Watch Co., the Caliber 8315 distinguishes itself within the "Standard Automatic" series through its remarkable endurance. This 21-jewel movement boasts a power reserve exceeding 60 hours, marking it as Miyota's most enduring mechanical offering.

Originating from Japan, the Miyota 8315 has a diameter of 26mm and stands 5.67mm tall. Operating at a beat rate of 21,600 bph (3 Hz), it features a rotor that winds in a counterclockwise direction. A notable aspect of this caliber is its Parashock anti-shock system, designed to bolster the watch's resilience against sudden impacts.

Functionality-wise, the Miyota 8315 supports central hour, minute, and sweeping second hands, along with a date display positioned at 3 o'clock. It also offers hacking seconds and quickset date adjustments. Under typical conditions, Miyota rates the accuracy of the 8315 at -20 / +40 seconds per day.

Building on the 8200 series foundation, the 8315 is compatible with a variety of 82XX series dials, hands, and cases.

Miyota 8315 watch movement

Seiko Caliber NH35A

Produced by Seiko Instruments Inc. (SII), part of the renowned Seiko Group, the Caliber NH35A is an evolution of the earlier NH25A model and has rapidly grown into one of the most sought-after automatic movements globally.

The NH35A presents a slightly larger profile than its counterpart, with a diameter of 27.4mm and a height of 5.32mm. It incorporates 24 jewels and shares the same 21,600 bph beat rate as the Miyota 8315.

Sporting a 41-hour power reserve, the NH35A features a Magic Lever for bi-directional winding, supports hand winding, and leverages Seiko's Diashock system for improved shock resistance. The movement accommodates central hour, minute, and sweeping second hands, along with a date function that may vary in position depending on the watch design. Hacking seconds functionality is also included.

Seiko reports the NH35A's accuracy to fall within -20~+40 seconds per day under standard usage. Notably, the NH35A is an unbranded variant of the Seiko Caliber 4R35, highlighting its adaptability across different watch models. .

Through this detailed examination, watch enthusiasts can appreciate the intricate details and distinctions that make the Miyota Caliber 8315 and Seiko Caliber NH35A both compelling choices in the world of horology.

 

In the realm of watch movements, the expertise of Japanese craftsmanship shines through the Miyota Caliber 8315 and Seiko Caliber NH35A. Here's a breakdown of their main features to help you understand what sets these two apart:

  • Origin: The Miyota Caliber 8315 hails from Miyota, a division of Citizen, while the Seiko Caliber NH35A is produced by Seiko Instruments Inc. (SII), a subsidiary of the Seiko Group.

  • Size Matters: The Miyota Caliber 8315 presents a more compact design with a 26mm diameter, whereas the Seiko Caliber NH35A is slightly larger at 27.4mm.

  • Slim Profile: Standing at 5.67mm, the Miyota is a tad taller than the Seiko's 5.32mm height.

  • Jewel Count: The Seiko Caliber NH35A incorporates 24 jewels, outdoing the Miyota Caliber 8315's 21 jewels.

  • Keeping Time: Both movements share a beat rate of 21,600 bph or 3 Hz, ensuring precise timekeeping.

  • Powering Through: With a 60-hour power reserve, the Miyota Caliber 8315 surpasses the Seiko Caliber NH35A's 41 hours.

  • Winding Ways: Miyota opts for a counterclockwise winding direction, contrasting with Seiko's bi-directional approach.

  • Shock Resistance: The Miyota employs the Parashock system, while Seiko relies on Diashock for enhanced durability.

  • Functional Finesse: Both movements feature central hour, minute, and second hands, along with a date display that usually sits at 3:00.

  • Precision: Accuracy for both movements falls within a range of -20 / +40 seconds per day.

Choosing Your Champion

Deciding between the Miyota Caliber 8315 and the Seiko Caliber NH35A boils down to personal preference and specific requirements. Opt for the Miyota 8315 if a longer power reserve and the robust Parashock system are priorities. If you prefer a watch movement with a larger diameter and a higher jewel count for enhanced performance and durability, the Seiko NH35A might suit you better. Additionally, the slightly lower cost of the Seiko NH35A could be a deciding factor for some.

Both movements exemplify the pinnacle of reliability and efficiency that Japanese watchmaking has to offer. Whether you're a discerning collector, an avid enthusiast, or a watchmaker, choosing either the Miyota Caliber 8315 or the Seiko Caliber NH35A ensures a solid foundation for any timepiece, combining excellent value with standout performance.