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The 2021 Seiko Presage Style60’s open-heart watches are the SSA423J1, SSA425J1 and SSA426J1. Seiko lists all three with automatic Caliber 4R39 and a June 2021 release. Their dial openings at 9 o’clock reveal the movement’s balance wheel in motion. The official specifications and design descriptions establish what these watches are; they do not establish independent accuracy, wearing comfort or comparative value.
Which Style60’s models have an open heart?
Seiko groups three references under the 2021 Style60’s open-heart description. Each uses automatic Caliber 4R39 and was listed as available from June 2021.
| Reference | Movement | Seiko-listed availability |
|---|---|---|
| SSA423J1 | Automatic Caliber 4R39 | June 2021 |
| SSA425J1 | Automatic Caliber 4R39 | June 2021 |
| SSA426J1 | Automatic Caliber 4R39 | June 2021 |
These are distinct from the other watches in the initial Style60’s release: SRPG03J1, SRPG05J1, SRPG07J1 and SRPG09J1, which Seiko lists with Caliber 4R35. Those references are part of the broader launch, but not the SSA-series open-heart trio. Seiko’s 2021 Style60’s collection page identifies the references, movements and release timing.
What does the open-heart dial show?
The opening sits at 9 o’clock and exposes the movement’s balance, the component Seiko describes as the movement’s “heart.” Its oscillation can be seen while the watch is running. This is a view of one moving part, not a view of the entire movement; Seiko’s product description identifies the visible component as the balance.
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- Polished And Brushed Stainless Steel
- 40.8mm Case Diameter
- 60s Style Inspiration
- Perforated Leather Strap
How does the design relate to the 1964 Crown Chronograph?
Seiko says the Style60’s draws inspiration from its 1964 Crown Chronograph. The brand points to box-shaped glass, faceted indexes and sharp hands as design cues, while describing the modern case as gently rounded with sides that slope inward. Polished lugs and contrasting finishes across the inner circular dial and outer index area add depth.
The collection uses dial colors including black, brown, ivory, blue and green or earth tones. Seiko also notes that some versions use slightly faded Lumibrite to reinforce the vintage-inspired look. These are collection-level design descriptions; they should not be taken to mean every color or detail appears on each of the three open-heart references.
Rank #2
- SEIKO WATCH – Seiko SRPL71 Presage wristwatch.
- COLLECTION – Presage Style 60's design.
- DESIGN – Mid-century-inspired color and case design.
- BRACELET – Hairline-finished bracelet links.
- WATCH DIAMETER – 39.5 mm.
What specifications can be confirmed—and what cannot?
For SSA423J1, SSA425J1 and SSA426J1, the cited 2021 Seiko material confirms the movement, open-heart placement and design family. It does not establish a complete model-by-model specification set or independent performance results.
A 2022 Seiko brochure provides specifications for later Style60’s references, not for the 2021 open-heart trio. For example, SSA453J1 is listed with Caliber 4R39, a 40.8 mm case, synthetic leather strap, box-shaped Hardlex glass, screw see-through case back and 5 bar water resistance. The same brochure lists SRPH93J1 and SRPH95J1 at 40.8 mm with Caliber 4R35 and their own case and strap configurations. These figures and specifications cannot safely be transferred to SSA423J1, SSA425J1 or SSA426J1. Seiko’s 2022 Style60’s brochure documents those later models.
Rank #3
- SEIKO WATCH – Seiko SRPL73 Presage wristwatch.
- COLLECTION – Presage Style 60's design.
- DESIGN – Mid-century-inspired color and case design.
- BRACELET – Hairline-finished bracelet links.
- WATCH DIAMETER – 39.5 mm.
Seiko’s official collection page and brochure are useful for confirming model identity and the brand’s stated design and specifications. They are not independent timing tests or evidence of how a particular example wears, so buyers seeking accuracy, condition, price or fit information should verify the exact reference and individual watch through current product documentation or the seller.
Quick Recap
Rank #4
- SEIKO WATCH – Seiko SRPL75 Presage wristwatch.
- COLLECTION – Presage Style 60's design.
- DESIGN – Mid-century-inspired color and case design.
- BRACELET – Hairline-finished bracelet links.
- WATCH DIAMETER – 39.5 mm.
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