Seiko NH36 vs 4R36: What's the Difference?

Quick Answer: The NH36 and 4R36 are essentially the same movement made by Seiko Instruments (SII). The difference is branding and distribution: NH36 is sold to third-party watch brands without Seiko branding, while 4R36 is Seiko-branded and used in Seiko's own watches. Specifications, reliability, and performance are identical.

Table of Contents

• The Short Answer
• Understanding Seiko's Movement Naming
• NH36 vs 4R36 Specifications
• Key Differences Explained
• Which One Should You Choose?
• Related Movements
• FAQ

The Short Answer

NH36 and 4R36 are the same movement with different names.

• 4R36 = Seiko-branded version, used in Seiko watches (Seiko 5, Prospex, etc.)
• NH36 = Unbranded/generic version, sold to third-party brands and modders

Think of it like store-brand vs name-brand cereal—same factory, same recipe, different box.

Understanding Seiko's Movement Naming

Seiko Instruments Inc. (SII) manufactures movements under two naming conventions:

For Seiko Watches (Branded)

For Third-Party Brands (Unbranded)

The "NH" prefix simply means it's sold without Seiko branding for use by other watch manufacturers and the mod community.

NH36 vs 4R36 Specifications

As you can see: identical specifications. The only differences are branding and availability.

Key Differences Explained

1. Rotor Branding

The most visible difference:

• 4R36: Rotor engraved with "SEIKO" logo
• NH36: Rotor is blank or marked "SII" (Seiko Instruments Inc.)

If your watch has an exhibition caseback, you'll see "SEIKO" on a 4R36 and nothing (or SII) on an NH36.

2. Availability

• 4R36: Only found inside Seiko-branded watches. You cannot buy it separately.
• NH36: Sold separately by parts suppliers. Available for $30-45 for modders and third-party brands.

3. Use Cases

• 4R36: Powers Seiko 5, Seiko Prospex, some Seiko Presage models
• NH36: Powers San Martin, Pagani Design, Heimdallr, SKYRIM, and countless other microbrands and mod builds

4. Quality Control

Both movements come from the same SII production lines. However:

• 4R36 in Seiko watches: Subject to Seiko's final QC before reaching consumers
• NH36 in third-party watches: QC depends on the brand using it

The movement itself is identical—but a $70 AliExpress watch may have less rigorous final inspection than a $300 Seiko 5.

Which One Should You Choose?

You Already Have a 4R36 If:

• You own a modern Seiko 5 Sports (SRPD series)
• You own certain Seiko Prospex divers
• You own some Seiko Presage models with day-date

In this case, you don't need to "choose"—you already have the Seiko-branded version.

Choose NH36 If:

• You're building a Seiko mod
• You're replacing a movement in a non-Seiko watch
• You want a day-date movement for a custom build
• You're buying a microbrand watch (most use NH36)

Movement Buying Guide

Related Movements: The Complete Family

NH/4R Series Comparison

Higher-Tier Alternatives

• 6R35: Seiko's upgraded caliber with 70-hour power reserve (found in higher-end Prospex and Presage)
• NE15/6R15: Higher-grade movement with better finishing
• Miyota 8285: Alternative day-date movement from Citizen's subsidiary

Frequently Asked Questions

Is NH36 a "fake" or "copy" of 4R36?

No. Both are genuine Seiko Instruments movements. NH36 is simply the version sold without Seiko branding to third parties. It's not counterfeit—it's how Seiko sells movements to the broader watch industry.

Can I replace a 4R36 with an NH36 (or vice versa)?

Yes. They're dimensionally identical. The only change would be the rotor branding visible through an exhibition caseback. All hands, dials, and cases compatible with one are compatible with the other.

Why do microbrands use NH36 instead of 4R36?

Because Seiko doesn't sell 4R36 separately. Third-party brands cannot buy Seiko-branded movements—they must use the NH-series generic versions. This is by design: Seiko protects its brand while still profiting from movement sales.

Is the NH36 reliable?

Extremely. The NH36/4R36 has been in production since 2011 with millions of units in circulation. It powers everything from $70 microbrands to $400 Seikos. Service is simple and inexpensive ($50-100 at any watchmaker), or you can simply replace the entire movement at that price point.

Does NH36 have hacking and hand-winding?

Yes. Both NH36 and 4R36 feature:

• Hacking: Second hand stops when crown is pulled out for precise time setting
• Hand-winding: Rotate crown clockwise to wind the mainspring manually

These features were absent in older Seiko movements (like the 7S26) but are standard in all 4R/NH calibers.

NH36 vs NH35: Which should I choose?

• NH35: Date only, thinner (4.8mm), compatible with date-window dials
• NH36: Day + date, thicker (5.32mm), compatible with day-date dials

Choose based on whether you want the day-of-week displayed. NH36 requires a dial with both day and date windows.

Conclusion

NH36 and 4R36 are the same movement wearing different name tags. If you're buying a Seiko watch, you'll get the 4R36. If you're building a mod or buying a microbrand, you'll get the NH36. Either way, you're getting a proven, reliable day-date caliber backed by Seiko's manufacturing expertise.

Don't overthink the naming—focus on what matters: both movements offer hacking, hand-winding, day-date complications, and the reliability that's made Seiko movements the backbone of affordable automatic watchmaking.