0

Your Cart is Empty

shop

62GS 36mm — Ultra Thin NH34-Ready Watch Case

Caseback

62GS Watch Case 36mm Ultra Thin with bezel-less box sapphire crystal and 4 o'clock crown

A Grand Seiko Icon. Reborn Ultra Thin. Built for GMT.

Inspired by the legendary Seiko 62GS, the 62GS Watch Case 36mm, part of our Ultra Thin Edition series, is a faithful reinterpretation of one of the most recognisable shapes in Japanese horology — rebuilt from the ground up around the NH movement and engineered to a profile most 62GS-style cases can't reach.

Two features define the 62GS architecture, and both are present here: a bezel-less construction where the crystal seats directly into the case top with no bezel ring, and a crown at 4 o'clock for a clean and symmetrical front profile. The case is finished with a multi-surface treatment — alternating polished and brushed planes with sharp, deliberate boundaries — that surpasses the complexity of our standard Explorer and GS cases.

The signature element is the box-shaped sapphire crystal — precision-cut with diamond tools at 1.4mm thick, raised and curved to honour the original 62GS profile. It's also cut to seat the SKX013-spec chapter ring within the crystal itself — the chapter ring lives inside the box sapphire, not under it. This is by far the hardest crystal we produce: thicker than our flat sapphires to absorb impact (the bezel-less construction leaves it structurally exposed), and shaped with internal precision to receive the chapter ring. It is our most advanced and highest-grade sapphire to date.

The other engineering feat: NH34 GMT compatibility. The case is fully NH34-ready — and at 11.3mm with the solid caseback, this is one of the thinnest 62GS-style cases available for a GMT NH movement.

Box sapphire pre-installed. Ready to assemble.
The box-shaped sapphire crystal ships pre-installed and aligned at our workshop — diamond-cut precision is the hardest part of a 62GS build, and we've handled it. You add the dial, hands, crown, chapter ring and movement, and you have a complete watch.

Bezel-less by design.
No bezel ring — the box-shaped sapphire seats directly into the case top, creating an uninterrupted profile from lug to lug. It's the silhouette that made the 62GS iconic in the first place, and it changes how light moves across the case.

Genuinely thin — with a deliberate tradeoff.
11.3mm with the solid caseback. The NH34 GMT movement alone is 7.99mm tall, leaving 3.6mm for everything else — and we deliberately spent most of that on a thicker, 1.4mm box-shaped sapphire. Bezel-less construction leaves the crystal structurally exposed with no bezel ring to protect it, so the sapphire has to carry that load itself. The result is a 62GS that honours the original silhouette without compromising on durability.

GMT-capable — the uncommon build.
Fully NH34-ready. Most 62GS-style cases can't take a GMT movement; this one does, without losing the slim profile. A thin 62GS GMT is a build few modders can make.

Multi-surface finishing.
316L steel with alternating polished and brushed planes — mirror-bright facets meeting satin surfaces at sharp, deliberate boundaries. The finish surpasses our standard Explorer and GS cases in complexity, and it's what gives this case its dress-sport character.

Caseback Total Thickness Water Resistance Best for
Solid · HEADLINE BUILD 11.3mm 100m / 10 ATM The thinnest profile — daily wear
Sapphire 12.2mm 100m / 10 ATM Movement display — show off the rotor

The solid caseback is the headline build — this is the case at its slimmest. The sapphire caseback adds slight thickness in exchange for a view of the NH movement.

Heads up — sold separately

Crown. The crown shown in product photos is for visual reference only. Crowns must be selected above — this case fits our 6mm Gen II and 7mm Diamond crown styles. Browse compatible crowns .

Chapter ring. This case requires a SKX013-spec chapter ring to seat the dial correctly — without it, the dial sits too low and hands won't clear. The case fits both normal and ultra thin chapter rings; the choice depends on your dial, not the case. If your dial has applied (raised) indices, choose ultra thin for clearance. If flat-printed, either works. When in doubt, ultra thin is the safer default. Browse compatible chapter rings .

For experienced modders only — TYPE M movements only

This case fits TYPE M versions of NH34, NH35, NH36, NH38, NH70, NH71, NH72 only. TYPE L will NOT fit. Due to tight clearance between hands and sapphire, this case is recommended only for professional watchmakers and experienced modders.

NH34 / GMT builds: for optimal second-hand clearance, the second hand must be under 12mm in length — or use a second-hand cap. Confirm before assembly.

  • Dimensions

    1. Case Diameter 36mm
    2. Case Thickness 11.3mm (Solid Caseback) / 12.2mm (Sapphire Caseback)
    3. Lug to Lug 43mm
    4. Lug Width 20mm

    Materials & Finish

    1. Quality Swiss Production Quality, ISO 9001 Certified
    2. Case Material 316L Stainless Steel
    3. Case Finishing Multi-surface — alternating polished and brushed planes with sharp boundaries
    4. Construction Bezel-less — crystal seats directly into case top
    5. Crown Position 4 o'clock
    6. Crown Screw-down — fits 6mm Gen II and 7mm Diamond crowns
    7. Crystal Box-shaped sapphire (1.4mm thick, internally cut to seat the chapter ring) with clear anti-reflective coating
    8. Crystal Size 31mm x 4.56mm

    Compatibility

    1. Movements TYPE M: NH34, NH35, NH36, NH38, NH70, NH71, NH72
    2. Dials 28.5mm
    3. Chapter Rings SKX013-spec (required, sold separately) — seats inside the box sapphire
    4. Hands NH movement compatible
    5. Crowns 6mm Gen II or 7mm Diamond
    6. Bracelets 20mm lug — all Lucius Atelier bracelets compatible

    Water Resistance

    1. Solid & Sapphire Caseback 100m / 10 ATM
  • New to Seiko modding? Here's everything you'll need for a complete, functioning watch — in the order you'd actually assemble it.

    What's already in this purchase:

    The case body with pre-installed box-shaped sapphire crystal, and your chosen caseback. That's the foundation. Everything below is what you'll add to make a wrist-ready watch.

    The 5 parts you'll need for a complete watch:

    1. Chapter ring — required first. The chapter ring seats inside the box sapphire, not below it — without it, the dial sits too low and the hands won't clear.
      (SKX013-spec — sold on a separate page. See the "sold separately" panel above for normal vs ultra thin guidance.)
      Browse compatible chapter rings
    2. Crown — 6mm Gen II or 7mm Diamond. Pick a style that matches the watch's character.
      (Required to add to cart. Selected from the dropdown above on this page.)
      Browse compatible crowns
    3. Dial (28.5mm) — the face of the watch. The biggest aesthetic choice you'll make. Match it to your chosen movement (date / day+date / GMT / no-date dial).
    4. Hands — paired with your dial. Most modders match lume colour across both hands and dial markers (BGW9 white-blue, C3 green, etc.). For NH34 GMT builds, you'll also need a GMT hand.
    5. Movement — NH34 (GMT), NH35 (date), NH36 (day+date), NH38 (no date), or source your own. The movement is the engine of the watch.

    Optional finishing touches:

    1. Bracelet or strap (20mm lug) — choose from Lucius Atelier oyster, jubilee, president, GS, Seikonaut, Settimo, or more designs, plus custom shell cordovan / full-grain cowhide leather straps.
    2. Decorated bridge + rotor (only visible with sapphire caseback) — replace the stock NH movement bridge and rotor with our Côtes de Genève decorated set, viewable through the sapphire caseback. Note: our bridges fit only our rotors (not OEM Seiko rotors), so they're chosen as a pair. Recommended for experienced modders only — or tick Assemble Watch below and we'll handle it.

    Want it built for you?

    Tick the Assemble Watch (+SGD $50) option above on this page and we'll handle the full build in our Singapore workshop — case fitting, movement seating, crown alignment, caseback press, function check, and decorated bridge + rotor installation if you've added those.

    Heads up: assembled watches require 2–5 business days of workshop time before shipping.

    Once your parts arrive, see the How To Mod tab for assembly tutorials.

    1. 1x Watch Case Body (with pre-installed box-shaped sapphire crystal)
    2. 1x NH Caseback (Solid or Sapphire, per selection)

    All photos of watches with modification parts are for illustration purposes only and are not included with the case purchase.

    1. A Complete Guide On How To Mod Your SEIKO Watch Dial And Hands (Photos & Video)
    2. Fitting dials with four dial legs
    3. Seiko Modding: The Complete Build Guide (2026)

Questions, Answered

Everything worth knowing before you build.

Can this case really take a GMT movement?

Yes. The 62GS 36mm is fully NH34-ready. Fitting a GMT caliber into a sub-12mm 62GS-style case is the engineering payoff of the Ultra Thin platform — and at 11.3mm with the solid caseback, this is one of the thinnest 62GS-style cases available for a GMT NH movement. Note the second-hand clearance requirement in the warning panel above.

What makes the 62GS different from a standard GS case?

Two architectural features set the 62GS apart: it's bezel-less — the crystal seats directly into the case top with no bezel ring — and the crown sits at 4 o'clock instead of 3. The case is also finished with a more intricate multi-surface treatment than our standard Explorer and GS cases, with polished and brushed planes meeting at sharp boundaries. Together they create the signature silhouette of the 62GS.

Which caseback should I choose?

The solid caseback (11.3mm) is the headline build — this is the case at its thinnest. Choose sapphire (12.2mm) if you want to display the NH movement and rotor through the back. Both are rated 100m / 10 ATM.

Why a box-shaped sapphire crystal?

The box shape is core to the 62GS identity — it sits proud of the case top with a raised, curved profile that catches light differently from a flat or domed crystal. Combined with the chapter ring nested inside it, the architecture creates a depth and dimension that other case-and-crystal combinations can't match.

Why is the sapphire crystal so much more complex than usual?

The 62GS box sapphire is the hardest and most expensive crystal we produce — and there are two reasons. First, the bezel-less construction leaves it structurally exposed with no bezel ring around it, so we engineered the sapphire at 1.4mm thick (thicker than our standard flat sapphires) to absorb impact safely. Second, the crystal is internally cut to seat the chapter ring within the sapphire itself — the chapter ring sits inside the box, not under it. That internal precision shaping pushes manufacturing complexity well beyond a standard flat or domed sapphire. The crystal alone reflects the engineering ambition of this case.

Does the 62GS 36 need a chapter ring?

Yes — the 62GS 36 requires an SKX013-spec chapter ring, sold separately. On this case it seats inside the box sapphire rather than below it; without it, the dial drops and the hands will not clear properly.

Will SKX007 dials fit the 62GS 36?

Any 28.5mm dial will fit. Note that the 62GS has a 4 o'clock crown position — so dial-foot orientation matters. Stock SKX007 dials are designed for a 4 o'clock crown with offset dial feet, which is a different geometry from our 3 o'clock-foot dials. Check your dial's foot positions before fitting.

What's the difference between Type M and Type L?

Type M and Type L are Seiko's two factory hand-fitting versions of the NH series. Type L sits higher than Type M — about 0.4mm taller from base to second-hand pinion. Because of the tight clearance between hands and sapphire in Ultra Thin Edition cases, only Type M will fit. Confirm your movement type before ordering.

Do I need to remove the sapphire crystal to install the chapter ring?

No — and that's the whole point of us pre-installing the sapphire for you. The chapter ring sits on top of the dial inside the case, not under the crystal, so the crystal stays where it is throughout the build. (If you ever do need to remove the sapphire — for example, to replace it — that's a workshop job we handle for you, not an at-home step.)

Should I choose the normal or the ultra thin chapter ring?

The choice depends on your dial, not the case — both sizes fit every Ultra Thin Edition case. If your dial has applied (raised) indices, the ultra thin chapter ring is the better choice because its slimmer profile gives the indices clearance instead of resting on top of them. If your dial is flat-printed (no applied markers), either size works. When in doubt, the ultra thin chapter ring is the safer default because it works with both dial types.

What is an SKX013 chapter ring and why does it matter?

A specific size and spec used by Seiko in the SKX013 (discontinued 2019). The LA smaller-case lineup all uses this same spec, which means dozens of chapter ring designs work across every smaller case in the catalogue.

Does this case need a chapter ring?

Yes — every Ultra Thin Edition case requires an SKX013-spec chapter ring, sold separately. The chapter ring seats the dial at the correct height; without it, the dial drops and the hands will not clear properly.