Seiko Mod Open Heart & Skeleton Watches

An open-heart watch reveals a working part of the movement through an opening in the dial. It is a choice for someone who wants more than moving hands: a small mechanical detail becomes part of an everyday glance at the time. Explore the builds listed with NH38 and compare their own specifications and configurations.

What NH38 and an open dial add

NH38 is an automatic movement. In an open-heart build, the dial opening lets you see part of its operation from the front. This is a construction and design feature, rather than a second time zone or stopwatch. If you need the time in another place, explore GMT watches.

Compare the size of the opening with the rest of the dial. Can you read the hands and markers easily? Some buyers enjoy the visible movement as the main detail; others prefer the quieter appearance of a full dial. Neither preference requires a more complicated watch.

Open-heart is not the same as skeleton

An open-heart dial exposes a selected area while retaining much of the dial surface. A skeleton design generally reveals more of the construction. The terms do not describe the same layout, and a wider view of the mechanism does not establish better accuracy. Compare the actual dial rather than relying on a category label.

Start with Chocolate Open Heart

Chocolate Open Heart combines a chocolate-brown dial with a rose-gold-tone case and an integrated bracelet. The opening gives its visible mechanics a distinct place within that colour combination.

Its product specification lists NH38, a 41 mm case, 12 mm thickness, sapphire crystal and an open case back. These details describe Chocolate, not every watch in this collection. Case diameter alone does not determine wrist fit; case shape and bracelet articulation matter too.

Choose the configuration, not just the photograph

Check the logo option and water-resistance rating offered for your chosen product. Chocolate has four combinations: LOGO or NO LOGO, each offered with a 3 ATM or 5 ATM option. Do not assume another product offers the same choices.

If water exposure matters to you, read the water-resistance guidance and ask about the selected configuration. A rating is not a substitute for care instructions or evidence of a test on an individual watch.

Make an informed choice

ModTime is an independent custom-watch brand. A movement name or reference-style term does not establish affiliation with another manufacturer. Before ordering, check the current shipping information and returns and complaints policy.

Start with the Chocolate Open Heart configuration, or ask ModTime about the model if you need a dimension or a clearer explanation before choosing.

Explore related collections: GMT watches · integrated bracelet watches · chronograph watches · watch travel cases · all watches

Questions before ordering? Read the ModTime FAQ or contact ModTime.

Need Help?

Frequently Asked Questions

What is a custom ModTime watch?

A ModTime custom watch is an independently assembled watch built from compatible components around a chosen movement, case, dial and bracelet.

The term "MOD" comes from "modification". These modifications are generally made for those who wish to personalize their watch according to their specific tastes or needs. Modifications can vary considerably, from minor aesthetic changes to more complex technical revisions.

What makes Seiko watches particularly amenable to modification is the wide availability of spare parts. This abundance of components enables a wide range of customization, making each ModTime custom watch unique.

Which movements do we use?

At ModTime, we work exclusively with reliable, high-grade Seiko movements — trusted by watch enthusiasts worldwide for their precision and durability.

Each movement is carefully selected and tested by our watchmaker to ensure optimal performance and a smooth mechanical experience.

We use:

  • NH34 Automatic — for our GMT Mods
  • NH35 Automatic — for date dial builds
  • NH38 Automatic — for clean dial designs without a date
  • VK63 Mecha-Quartz — for chronograph models


Every ModTime watch is powered by a movement chosen for its accuracy, longevity, and craftsmanship — the foundation of every timepiece we create.

Can I adjust the watch size myself?

Absolutely! Every ModTime timepiece comes with a FREE complimentary premium adjustment kit, allowing you to resize your bracelet easily and safely at home.

Each tool is designed for precision and comfort — the same way our watches are crafted.

If you prefer, your local watchmaker can also assist you with the adjustment — our bracelets use standard Seiko-compatible links, making professional resizing simple and effortless.

Can I choose a clean or dial-marked version?

Yes — absolutely! Every ModTime timepiece can be fully customized to match your personal vision.

If you prefer a clean, minimalist dial without visible dial branding, our watchmakers will assemble your piece accordingly during the hand-crafting process.

Simply include your preference in the order notes at checkout, and we’ll ensure your watch is built exactly the way you want it — refined, personal, and uniquely yours.

Can I design my own watch?

Absolutely. At ModTime, every timepiece can be crafted to your personal vision — from the bracelet and case to the dial, hands, and finishing details.

You can even add your own logo or initials, turning your watch into a truly one-of-a-kind creation.

If you’d like to design a fully personalized ModTime piece, simply reach out to us on WhatsApp. Our watchmakers will guide you through every step of the customization process — from concept to final assembly.

Shipping Time and Costs

Each watch is hand-assembled within 4-6 days to ensure the highest quality and attention to detail.

Once completed, the shipping time is 7-12 days, depending on your location. While we aim for prompt delivery, some variations may occur based on the destination.

Please note: Due to the current global shipping conditions, especially related to parcel traffic in and out of the US, delivery times may occasionally be slightly extended. However, we do everything on our side to ensure the fastest possible handling and dispatch.

Please note that delivery times may vary depending on the destination country.

Are the watches water resistant?

ModTime watches use variant-dependent water-resistance options such as 3 ATM or 5 ATM. 3 ATM is intended for daily splashes and rain. 5 ATM gives more everyday margin, but custom watches should still be kept away from swimming, bathing, diving and prolonged water exposure unless a specific model is explicitly rated for that use.

No answer matches that yet. Try a broader word — or reach our watchmakers on WhatsApp and we’ll help directly.