Seiko NH35(4R35) vs Miyota 8215 vs Miyota 9015

Summary of Key Specifications

1. Frequency:
   The Miyota 9015 runs at 28,800 vph, offering a smoother sweep.
   The NH35 and 8215 operate at 21,600 vph.

2. Thickness:
   The 9015 is thinner (3.9 mm), allowing for slimmer cases.
   The NH35 (5.32 mm) and 8215 (5.67 mm) are noticeably thicker.

3. Functions:
   All three calibers offer hours, minutes, seconds, and date.
   The NH35 and 9015 support hacking (stop-seconds), while the 8215 does not.

4. Durability & Reliability:
   The NH35 and 8215 are known for being very robust and reliable.
   The 9015 is also stable, though its thinner construction can make it slightly more sensitive to shocks.

5. Rotor Noise:
   The 9015 and NH35 are quiet in operation.
   The 8215 has a more audible rotor, though it isn’t bothersome in everyday use.

MIYOTA 9015 – The High-End Option Among Affordable Movements

The MIYOTA 9015 (9S series) is the high-end model of the Miyota line. With a thickness of just 3.9mm, it is the thinnest among the three budget-friendly movements we’re discussing. In the watchmaking world, anything under 4mm is considered a slim movement. For comparison, the ETA 2892 measures 3.6mm—so the 9015 is only 0.3mm thicker.

This movement runs at a 4Hz frequency (28,800 bph), the highest among the three, which theoretically allows for the best accuracy. Based on my personal experience, after careful regulation, it can achieve a daily deviation of ±5 seconds.

The 9015 features uni-directional winding and a 42-hour power reserve. Its slim profile makes it particularly suitable for dress watches, while the movement finishing is noticeably higher quality than the 8-series Miyota movements.

In terms of cost, the 9015 is also the most expensive among the three. Besides the standard date version, there is also a skeletonized variant called the 90S5, offering a more visually striking option.

If you’re looking for a watch that combines the high-end Miyota 9015 movement with incredible value, our ADDIESKIN K001 is one of the most affordable watches on the market featuring this movement. With its slim profile, refined finishing, and elegant “Eye of Exploration” design, it’s a perfect choice for those who want premium performance without breaking the bank.

SEIKO NH35 (SEIKO 4R35) – Reliable Workhorse Movement

With a thickness of 5.32mm, the NH35 is not particularly thin. It runs at 3Hz (21,600 vibrations per hour) and features bi-directional automatic winding via SEIKO’s patented Magic Lever system. The design is straightforward: a Y-shaped Magic Lever either connects directly to the rotor’s center or through a small gear train to drive the lever. The lever engages with the winding wheel using an eccentric pivot, allowing the mainspring to be wound as the rotor swings clockwise (pulls down) or counterclockwise (pushes up).

This system is conceptually similar to IWC’s Pellaton winding, offering very high efficiency. In practice, the watch can reach full wind in roughly half a day to a full day of wear. The only drawback is potential wear on the hook tip of the lever over long-term use.

The NH35 has a 41-hour power reserve and uses a simple regulator for fine adjustment. Compared to SEIKO’s entry-level 7S series, the NH35 (4R series) adds hacking (stop-seconds) and manual winding via the crown, significantly improving practicality and everyday usability.

MIYOTA 8215 – The Most Economical and Versatile Movement

The MIYOTA 8215 (8-series) is currently one of the most affordable and widely used movements on the market. With a thickness of 5.67mm, it is slightly thicker than the NH35 and 9015. It features uni-directional automatic winding, which, compared to bi-directional winding, is easier to assemble and maintain and has a lower risk of malfunction. However, winding efficiency may be slightly lower.

The movement runs at 3Hz (21,600 vibrations per hour) and offers a 40-hour power reserve. It does not have a hacking (stop-seconds) function, as it lacks a stop-seconds lever. When setting the time, it is recommended to turn the crown clockwise, since turning it counterclockwise may cause the second hand to pause or even run backward, potentially stressing the gear train.

For those who prefer the economical yet reliable MIYOTA 8215, we recommend checking out watches like the ADDIESDIVE AD2093 and AD2526. Both models feature the classic 8215 movement, offering solid performance, durable construction, and stylish designs at an entry-level price point. These watches are perfect for anyone looking to enjoy automatic watch functionality without overspending.

Conclusion: Which One Is Right for You?

✅ Choose the NH35 if you value:

• Very precise time-setting

• Quiet and stable operation

• Strong overall performance

✅ Choose the Miyota 9015 if you’re looking for:

1. A smoother movement (28,800 vph)

2. A slimmer and lighter case design

3. A very quiet and smooth rotor in daily wear

✅ Choose the Miyota 8215 if you’re looking for:

1. A more affordable price

2. Classic, no-frills mechanics

3. A reliable watch for everyday use

At AddiesKIN, we use the  Miyota 9015 to offer watches that are reliable, well-built, and thoughtfully designed for everyday wear. If you’re looking for a durable watch with character and refined mechanics, explore our full collection here:
👉 AddiesKIN Mechanical Watches for Men

Whichever you choose, you’ll enjoy the precision of an automatic movement and the timeless appeal of a well-made dive watch.