Fifty-five years ago, Seiko introduced its, and Japan’s, first ever diver’s watch. With an automatic movement and water resistance to 150 m, it proved its reliability when it was used by members of the Japanese Antarctic Research Expedition from 1966 to 1969. In the years that followed, Seiko created many other diver’s watches that became favorites of professional divers and adventurers of all kinds, thanks to their high quality and reliability.

Three landmark designs from Seiko’s first decade as a maker of diver’s watches are now re-created as a trilogy in celebration of the 55th anniversary of that first achievement – the original 1965 design, Japan’s first 300m water – resistant watch from 1968 and the revolutionary 1975 saturation diver. And, fittingly, they are offered as part of the Prospex collection, synonymous today with timekeeping excellence for sports and all types of challenging environments.

Although proud that their watch had proved itself in the Antarctic, Seiko’s engineers continued their development work to better meet the demanding requirements of the professional diver. This was the goal that lead in 1968, to Seiko’s first diver’s watch with 300 m water resistance and a 10-beat automatic movement, used successfully by the first person from Japan to climb Mt. Everest. That same year, however, came a letter from a professional diver who explained to the engineers that no diver’s watch yet created could withstand the conditions that he faced every day in his job as a saturation diver.

The Seiko team realized that nothing less than a technical leap was needed to create a diver’s watch that could truly be called “professional.” It took seven years but, at last, in 1975, Seiko produced a 600 m diver’s watch that pushed the boundaries further than any other diver’s watch in history. It had a one-piece titanium case and an outer case protector. Among a host of innovations was a specially developed L-shaped gasket to make the watch impervious to helium without the need for an escape valve, as well as an accordion-style strap that kept the watch secure on the wrist whatever the ambient pressure. This unique watch changed the world’s expectation of what a diver’s watch could deliver forever and its distinctive construction led watch fans across the world to give it the nickname “Tuna.”

While faithful to the original designs, all three new watches offer upgraded specifications and execution. The greatest advance is in the grade of stainless steel used in the construction of the three watches. Known as Seiko’s “Ever-Brilliant Steel,” thanks to the brilliant white hue that gives this trilogy of watches its unique look, this grade of steel is more corrosion resistant than that used in most of the highest-end watches today. * It will be used for the first time** in the watch industry for the cases of the 1965 and 1968 re-creations as well as the bezel of the 1975 re-creation, which, like the original, has a titanium case. This material has been used extensively in the surfaces, linings, bolts and other components of marine structures and vessels to avoid corrosion in a chloride-rich environment such as sea water. It poses many challenges in the manufacture of watch cases but, thanks to the experience and innovative techniques of the Seiko team, Ever-Brilliant Steel is now set to bring a new level of durability to the diver’s watch.

The 1965 and 1968 re-creations are powered by the high beat 8L55 movement and the 1975 re-creation includes a Caliber 8L35, both developed and assembled expressly for diver’s watches at Seiko’s Shizukuishi Watch Studio. All three have sapphire crystals with anti-reflective coating on the inner surface. Thanks to its pure iron dial, the 1975 re-creation also has an increased anti-magnetic resistance of 40,000 a/m. 

* This stainless steel has a PREN (Pitting Resistance Equivalent Number) value 1.7 times higher than that of the grade of steel used in most high-end watches. PREN is a widely accepted standard used to measure corrosion resistance. 

** as of December 2019, based on Seiko’s research.

All three re-creations share the same blue-gray dial, evoking both the beauty of the sea and their ability to perform at the darkest depths. In particular, the subtle gradation of the dial color on the 1965 and 1968 re-creations dramatizes the way that light gradually fades as one dives deeper into the dark, mysterious world of the ocean.