The Seiko Watch Automatic Presage SSA405J1 is an enchanting expression of Japanese mechanical horology, mid-century retro elegance, and the glamorous mixology culture of Tokyo’s Ginza district. Drawing creative inspiration from the bespoke “Blue Moon” cocktail shaken by master mixologist Hisashi Kishi at the world-renowned Star Bar, this timepiece captures the quiet magic of twilight giving way to night. Engineered specifically for discerning gentlemen seeking a men midnight blue sunburst open heart automatic dress watch, the SSA405J1 elevates traditional dress-watch styling by revealing the pulsating mechanical heartbeat directly through the dial, making it an extraordinary accessory for black-tie galas, formal business meetings, and elevated evening celebrations.

Captivating Blue Moon Dial with Open-Heart Aperture

The defining soul of the SSA405J1 is its deeply pressed radial sunburst dial, finished in an alluring gradient of midnight blue with a glossy clear lacquer topcoat. Mimicking the liquid light refractions of a craft cocktail held in a crystal coupe glass, the dial shifts dynamically between rich cobalt and deep twilight navy under ambient light. At the 9 o’clock position lies a circular open-heart aperture, offering an intimate, unobstructed view of the escapement and ticking balance wheel. Polished dauphine hands glide gracefully across razor-sharp faceted arrow indices, accompanied by an electric blued central seconds hand designed to evoke the slender form of an artisan cocktail stirrer.

Classic Ergonomics and Box-Shaped Hardlex Crystal

Housed in surgical-grade stainless steel with alternating mirror-polished and brushed surfaces, the case measures an ergonomic 40.5mm in diameter, 11.8mm in thickness, and 47.5mm lug-to-lug. These versatile proportions provide a commanding wrist presence while slipping effortlessly beneath tailored shirt cuffs and formal suit jackets. Protecting the intricate dial is Seiko’s vintage-inspired box-shaped Hardlex crystal, which introduces warm optical distortions along the curved perimeter to enhance its 1960s cocktail lounge aesthetic. An oversized grooved crown at 3 o’clock ensures a firm, tactile grip for effortless hand-winding.

In-House Mechanical Precision: Seiko Calibre 4R38

Beating inside is the dedicated in-house Seiko Calibre 4R38 automatic movement, purpose-built for open-heart dial displays. Operating at 21,600 vibrations per hour across 24 jewels, this self-winding engine provides an approximate 41-hour power reserve. It features manual hand-winding capability and a hacking stop-seconds function for pinpoint time synchronization. Through the exhibition screw-down case back, owners can view the decorated movement and gold-toned oscillating rotor at work.

Supple Calfskin Leather Strap with Deployment Clasp

The SSA405J1 comes fitted on an elegant dark blue-toned cow leather strap with subtle contrast stitching. It fastens securely with a stainless steel three-fold clasp with push-button release, preserving the leather against premature wear while ensuring rapid, dependable closure. Built for confident everyday wear, the watch provides 5 bar (50 meters) water resistance and 4,800 A/m magnetic resistance.

An Enduring Japanese Horological Masterpiece

Backed by Seiko’s official international manufacturer warranty, the Seiko Presage SSA405J1 “Blue Moon” Open Heart stands as an enduring tribute to Japanese artisanal pride. It remains a captivating mechanical centerpiece ready to elevate any curated timepiece collection.