Seiko Prospex Marinemaster
1968 Heritage Diver's Watch
Seiko’s journey in diver’s watchmaking began in 1965 with Japan’s first diver’s watch, which
accompanied members of the Japanese Antarctic Research Expedition to the South Pole from 1966 to
1969. This model was followed by the creation of the nation’s first 300m water-resistant diver’s
watch in 1968.
In the decades since, Seiko has developed new technologies, designs, and features that have made its
diver’s watches a trusted favorite of professionals and enthusiasts worldwide.
Based on the design of the 1968 diver’s watch, a regular model equipped with Caliber 8L45 joins
the Marinemaster series.
The dial’s deep black hue and fine-grain texture minimize light reflection from the dial while
the beveled edges of the indexes catch light from any angle, delivering high visibility.
The bezel insert, made from glossy ceramic, offers excellent scratch resistance.
Inheriting the flowing silhouette and the 4 o’clock crown design of the 1968 model, it
proudly bears the name ‘1968 Heritage Diver’s Watch.’
Its appeal lies not only in its outstanding performance, but also in the refined beauty of
its exterior design and the meticulous finishing evident in every detail.
The watch features an updated clasp that offers easy adjustments of up to 16mm in 2mm increments by sliding the button inside. Even when the clasp is closed, the extension can be retracted, ensuring comfortable and effortless operation.
Caliber 8L is a high-quality mechanical movement that embodies Seiko’s expertise in mechanical
watchmaking, along with an uncompromising spirit of craftsmanship passed down through
generations of skilled watchmakers.
With Caliber 8L45, Seiko has improved the shape and design of the mainspring and implemented
precise accuracy adjustments, achieving the highest accuracy (-5 to +10 seconds per day) among
Seiko’s current mechanical movements and a power reserve of approximately 72 hours.
Seiko’s legacy of testing the limits of the modern sports watch and supporting marine conservation
continues through its partnership with the Japan Agency for Marine-Earth Science and Technology
(JAMSTEC), which began in the 1980s. In 1983, two professional diver’s watches rated to 600 meters
were successfully tested aboard the SHINKAI 2000, a manned research
submersible which was operated by JAMSTEC.
Inspired by the spirit of bold exploration that connects JAMSTEC and Seiko, a new limited-edition
diver’s watch joins Prospex’s flagship Marinemaster series.
The Japan Agency for Marine-Earth Science and Technology (JAMSTEC) is a national institute for comprehensive marine research and development dedicated to advancing innovative science and technology. JAMSTEC fosters academic progress and deepens understanding of the Earth and life, while contributing to the sustainable development of society and the preservation of the global environment. Using data obtained through its research, JAMSTEC strives to address societal and economic needs and drive innovation across multiple sectors.
The dial’s new three-dimensional pattern takes inspiration from the tracks carved through sea
ice by icebreaking vessels.
Its blue gradient, which deepens toward the center, combines with a thick, transparent coating
that is meticulously polished to create exceptional clarity and depth. Together, these elements
evoke the pure, profound blue that emerges within the Arctic Ocean, revealed amidst the vast
expanse of drifting sea ice.
The design features a blue ceramic bezel that enhances the beauty of the dial while
providing exceptional scratch resistance.
With Caliber 8L45, Seiko has improved the shape and design of the mainspring and implemented
precise accuracy adjustments, achieving the highest accuracy (-5 to +10 seconds per day)
among Seiko’s current mechanical movements and a power reserve of approximately 72 hours.
The watch features an updated clasp that offers easy adjustments of up to 16mm in 2mm increments by sliding the button inside. Even when the clasp is closed, the extension can be retracted, ensuring comfortable and effortless operation.
