Watch 3 — Spec (concept stage)

Status: future — open for refinement after Watch 2 ships Concept: The open-heart / exhibition build — movement as design element New skill this build introduces: Sourcing a movement specifically because it is interesting to look at. Treating finishing, rotor, bridges, and dial cutout as design decisions.

Aesthetic

• Movement visible from the dial side (open heart) and/or through an exhibition caseback
• 39–41mm case, slightly bigger than Watch 2 to accommodate a more complex movement and the cutout
• Skeletonized or open-heart dial — the cutout placement is a real design decision
• Hand style chosen to NOT obstruct the open-heart cutout in the 6 to 8 o'clock area (typical open-heart placement)

Constraints — early thinking

• Movement options:
  • Miyota 82S5 — open heart variant of the 8215. Visible escapement at the dial side.
  • Skeletonized NH variant — DSWatch and NamokiMODS both sell skeletonized NH35-compatible options, but quality of finishing varies.
  • Sea-Gull ST series — Chinese-manufactured movements with more interesting visible finishing at modder price points.
  • Decision criterion: the movement must look good. Photograph candidates under angled light before purchase.
• Case: must have an exhibition caseback (clear sapphire back) AND must accommodate the open-heart dial cutout from the front. Tandorio offers exhibition-back variants on their NH35-fit cases.
• Dial: the cutout placement is dial-design territory. Off-the-shelf open-heart dials exist but are usually 7–8 o'clock cutouts. A 6 o'clock cutout is more dramatic; a 9 o'clock cutout is unusual.
• Hands: should not extend over the cutout. If the cutout is at 7–8, the second hand at full sweep crosses it — this is fine and intentional, but the hour hand needs to stay clear at all times.
• Crystal: sapphire, flat or low-dome — the dial is the show, not the crystal.

Skills to demonstrate (acceptance criteria for "Watch 3 done")

• Movement chosen for visual quality, not just specs
• Open-heart cutout aligned correctly with the movement's visible bridge/wheel
• Hand setting accounts for the cutout (no rub, no obstruction)
• Exhibition caseback shows the rotor finishing well — caseback grease applied without smearing the inside of the sapphire

Sourcing strategy — early thinking

• Movement: Miyota 82S5 from a US distributor (Otto Frei sells these), Esslinger, or direct from a maker via a dealer. Confirm the rotor is finished (not bare) — bare rotors are uninspiring through an exhibition back.
• Case: Tandorio's Miyota-fit cases with sapphire backs are the starting point; alternative is NamokiMODS exhibition-back NH35 cases (which would limit movement choices to NH-family).
• Dial: open-heart dials from DSWatch or NamokiMODS. Verify cutout positioning matches the movement's visible bridges. Photograph the movement first; size the dial cutout to that specific movement, not generic.
• Hands: Dauphine, sword, or syringe styles — anything that doesn't visually clutter the open-heart area. Probably C1 or C3 lume — match the dial's lume choice.
• Crystal: Cousins UK domed sapphire, sized to case seat.
• Strap: depends on whether this is a sport-leaning or dress-leaning open heart. Probably leather, possibly a sailcloth/perlon for variety.

Open questions

• Is this a dress-leaning open heart (39mm, polished, leather strap, dark dial) or a sport-leaning one (41mm, brushed, NATO strap, bright dial)?
• Should the open heart be at 6 o'clock (dramatic) or 7–8 (conventional)?
• Skeletonized full-dial vs partial open heart cutout?

Risk register

• Movement looks bad through the cutout: unrecoverable without re-buying movement. Mitigation: photograph the movement under angled light before buying.
• Cutout doesn't align with movement bridges: dial is wrong; rebuy. Mitigation: confirm dial cutout dimensions against the specific movement, not a generic one.
• Hand obstructs the cutout view: hand-setting error; lift and re-press at correct height. Generally minor.
• Caseback gasket smudges the inside of the exhibition sapphire: unsightly. Mitigation: very thin gasket grease coat, gasket seated cleanly before close.

Open items

• Dress-leaning vs sport-leaning aesthetic
• Movement choice (Miyota 82S5 vs skeletonized NH vs Sea-Gull)
• Cutout position on dial
• Strap type (leather, sailcloth, perlon, NATO)

Watch 3 — Parts List

Source of truth for order status. Update rows in place — do not append duplicates.

Status values: proposed → ordered → shipped → received → installed

Spares / consumables

(empty until parts list firms up)

Watch 3 — Build Log

Append-only chronological journal. New entries go at the bottom under a dated header.

Format: ## YYYY-MM-DD — short title

(empty until Watch 2 ships and Watch 3 sourcing begins)

Watch 3 — Notes

Free-form observations, mistakes, things to remember for future builds. Items here that generalize beyond watch_003 should be promoted to sourcing/compatibility_notes.md or sourcing/parts_database.md.

Pre-build observations (2026-05-10)

• The open heart only works if the movement is finished well. Unfinished bridges and a stamped rotor look cheap through an exhibition back. The pre-purchase photography of the candidate movement is the most important sourcing step in this build.
• Cutout-to-movement alignment cannot be fudged. Off-the-shelf open-heart dials assume a specific movement family (NH3x or Miyota 82xx). Cross-fitting is high-risk.
• Open-heart dials carry less printed/applied real estate than full dials, so the print quality on what IS on the dial matters more — every flaw is closer to the cutout boundary and harder to hide.