Seiko Prospex Emperor Tuna Marinemaster 1000M SBDX013

The Seiko Prospex Marinemaster 1000M "Emperor Tuna" SBDX013 is one of the most capable and iconic professional dive watches ever produced by Seiko. Nicknamed the **"Emperor Tuna"** by enthusiasts for its imposing size and commanding wrist presence, this reference represents the pinnacle of Seiko's legendary Tuna lineage—a collection born from decades of innovation driven by the demands of professional saturation divers. Introduced in 2015, the SBDX013 features a massive 52.4mm titanium monocoque case protected by a black ceramic outer shroud, creating an incredibly robust construction that is both lightweight and exceptionally resistant to corrosion and impact. Its matte black dial, oversized LumiBrite markers, sapphire crystal, and signature shrouded design prioritize maximum legibility and durability, while the distinctive silhouette has made the Emperor Tuna one of the most recognizable dive watches in the world.

Powering the SBDX013 is Seiko's premium Caliber 8L35 automatic movement, a high-performance mechanical caliber assembled at the Shizukuishi Watch Studio and derived from the architecture of Grand Seiko's renowned mechanical movements. Operating at 28,800 vibrations per hour with a 50-hour power reserve, the movement delivers exceptional reliability for demanding underwater environments. Engineered for **1,000 meters of saturation diving**, the Emperor Tuna features a one-piece titanium case, screw-down crown, anti-magnetic protection, and a professional-grade silicone strap designed for use over a wetsuit. Revered by collectors as one of Seiko's ultimate tool watches, the SBDX013 combines uncompromising engineering, decades of diving heritage, and unmistakable design, securing its place as one of the finest professional dive watches ever produced by the Japanese manufacture.

Reference: SBDX013

Bezel Aligns

Bracelet: Black Silicon Isof Strap (Aftermarket)

Case Size: 52.4mm x 17.2mm Thickness

Case Metal: Titanium case with super-hard coating and ceramic

Movement: Seiko 8L35 - Automatic

Functions: Hours, Minutes, Second, Date

Box and Papers: Box and papers

Crystal: Sapphire

Bracelet size: 7.75”

Case has some light wear. Strap has no wear. Dial, hands, and crystal are in prefect shape. Running spec.

Seiko's history began in 1881 when Kintaro Hattori opened a watch shop in Tokyo. In 1892, he established Seikosha, a factory for producing wall clocks. The company quickly progressed, creating Japan's first wristwatch, the Laurel, in 1913. Despite setbacks like the Great Kanto Earthquake of 1923, Seiko persevered, launching its first watch under the Seiko brand name in 1924.

The post-World War II era saw Seiko's rapid growth and innovation. They introduced Japan's first automatic wristwatch in 1956 and launched the prestigious Grand Seiko line in 1960. Seiko achieved international recognition for accuracy in 1968, winning a Geneva Observatory competition. 

The company made a name for its divers in 1965 with the introduction of their first professional dive watch, the 62MAS. This was followed by the iconic 6159-7001 in 1968, which was water-resistant to 300 meters. Seiko gained international recognition in 1975 with the release of the 6159-7010, nicknamed the "Tuna Can" due to its distinctive case shape. In 1969, they revolutionized the industry with the Astron, the world's first quartz wristwatch, ushering a new era of watchmaking that would send waves across the industry through the 70s and 80s. From its humble beginnings to becoming a global watchmaking giant, Seiko's history is characterized by resilience, technological advancement, and a commitment to precision.