Orient Sun & Moon vs Seiko Presage SSA425 Open Heart
Orient's dress watch meets Seiko's timepiece
Quick Verdict
The Orient Sun & Moon ($250–$500) and Seiko Presage SSA425 Open Heart ($250–$500) are closely matched timepieces at similar price points. The Sun & Moon emphasizes Orient In-House Automatic (Hacking, Hand-Winding) engineering while the Presage SSA425 Open Heart focuses on Made in Japan craftsmanship.
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Specifications Compared
| Feature | Orient Sun & Moon | Seiko Presage SSA425 Open Heart |
|---|---|---|
| Price | $250–$500 | $250–$500 |
| Case Size | 41.5mm | 40.5mm |
| Movement | Automatic Caliber F6B24 | Automatic Caliber 4R38 |
| Caliber Type | Orient In-House Automatic (Hacking, Hand-Winding) | Seiko In-House Automatic |
| Power Reserve | 40 Hours | 41 Hours |
| Water Resistance | 50m (5 ATM) | 50m (5 ATM) |
| Crystal | Mineral Glass | Hardlex Crystal |
| Case Material | Stainless Steel | Stainless Steel |
| Origin | Made in Japan | Made in Japan |
Category-by-Category Analysis
Design & Aesthetics
Orient's design language vs Seiko's approach
The Orient Sun & Moon features a Stainless Steel case at 41.5mm with Mineral Glass protection. The Seiko Presage SSA425 Open Heart offers Stainless Steel construction at 40.5mm with Hardlex Crystal. Both represent their brand's distinct design philosophy and heritage.
Movement & Performance
Automatic Caliber F6B24 vs Automatic Caliber 4R38
The Sun & Moon runs the Automatic Caliber F6B24 (Orient In-House Automatic (Hacking, Hand-Winding), 40 Hours power reserve) at 21,600 vph (3 Hz) frequency. The Presage SSA425 Open Heart uses the Automatic Caliber 4R38 (Seiko In-House Automatic, 41 Hours reserve) at 21,600 vph (3 Hz). The Presage SSA425 Open Heart offers a longer power reserve.
Wearability & Fit
41.5mm vs 40.5mm — different wrist presence
At 41.5mm, the Sun & Moon has a bolder wrist presence compared to the Presage SSA425 Open Heart at 40.5mm. Water resistance differs: 50m (5 ATM) vs 50m (5 ATM).
Value & Cost of Ownership
Same tier — different value propositions
The Orient Sun & Moon sits at $250–$500 and the Seiko Presage SSA425 Open Heart at $250–$500. On the specs that outlast any price: the Sun & Moon uses Mineral Glass with 40 Hours, against Hardlex Crystal and 41 Hours on the Presage SSA425 Open Heart. Service intervals are typically 5-7 years for both.
Water Resistance
50m (5 ATM) vs 50m (5 ATM)
The Sun & Moon is rated to 50m (5 ATM) while the Presage SSA425 Open Heart handles 50m (5 ATM). Both offer identical water resistance ratings.
Our Verdict
Orient
Sun & Moon
Choose the Orient Sun & Moon if you prioritize Orient In-House Automatic (Hacking, Hand-Winding) engineering, Made in Japan craftsmanship, and 50m (5 ATM) water resistance. At $250–$500, it delivers Automatic Caliber F6B24 with 40 Hours power reserve.
Check Price on AmazonSeiko
Presage SSA425 Open Heart
Choose the Seiko Presage SSA425 Open Heart if you value Seiko In-House Automatic technology, Made in Japan heritage, and 40.5mm proportions. At $250–$500, the Automatic Caliber 4R38 with 41 Hours power reserve makes it a compelling choice.
Check Price on AmazonThe Bottom Line
The Orient Sun & Moon and Seiko Presage SSA425 Open Heart represent two distinct approaches to fine watchmaking — the Orient bringing Made in Japan tradition while Seiko delivers Made in Japan engineering.
Frequently Asked Questions
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How This Page Was Made
Our comparisons are generated from a hand-maintained specification database and reviewed under our editorial standards. We use AI tools to assemble pages from that data. We don’t invent specs: every number traces back to the database, and when we correct an entry, the fix is applied site-wide. As an Amazon Associate, The Horologist earns from qualifying purchases.