Celebrating 55 years of Seiko diver’s watches, three legends are re-born in Prospex

55 years ago, Seiko introduced its, and Japan’s, first-ever diver’s watch. With an automatic movement and water resistance to 150m, 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 found favour with professional divers and adventurers alike, thanks to their high quality and reliability. Seiko launched three re-creations that combine heritage and evolution – Seiko Prospex SLA037, SLA039, SLA041 & SPB149.

Three of the most important landmarks from Seiko’s first decade as a maker of diver’s watches are now re-created in celebration of the 55th anniversary of that first achievement. They are offered in the Prospex collection which is today synonymous with excellence in watches for use in all types of sports and challenging environments.

Although proud that their watch had proved itself in the Antarctic, Seiko’s engineers continued their development work to better meet the needs of the professional diver. This is why, in 1968, Seiko’s first diver’s watch with 300m water resistance and a 10-beat automatic movement was created. It was used successfully by the first person from Japan to climb Mt. Everest but this achievement was, at least partially, eclipsed by the receipt that same year of a letter from a professional diver who quietly asserted that no diver’s watch yet created could withstand the conditions that were his everyday reality in his job as a saturation diver. The Seiko team realized that nothing less than a technical step-change 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 600m diver’s watch that pushed back the boundaries further than perhaps any other diver’s watch in history. It had a titanium one-piece case and an outer case protector. It used a specially developed L-shaped gasket to make it impervious to helium without the need for an escape valve. It had an accordion-style strap that made the watch secure on the wrist whatever the ambient pressure. This unique watch changed forever the world’s expectation of what a diver’s watch could deliver and its unique construction and popularity led to it being given the name “Tuna” by watch fans across the world.

While faithful to the original designs, all three watches are fully up to date in their specifications and execution. The greatest advance is in the grade of stainless steel used in the construction of the three watches. To be 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 which is used in most high-end watches today.* It is used for the first time** in the watch industry for the cases of the 1965 and 1968 re-creations and the bezel of the 1975 re-creation whose case is, like the original, in titanium. This material is used extensively in the surfaces, linings, bolts and other components of marine structures and vessels so as to avoid corrosion in a chloride-rich environment such as sea water. It presents many challenges in the manufacture of watch cases but, thanks to the experience and innovative techniques of the Seiko team, these challenges were overcome and 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 carries Caliber 8L35, both developed and assembled expressly for diver’s watches at the Shizukuishi Watch Studio. All three have sapphire crystals, and the 1975 re-creation has an increased anti-magnetic resistance of 40,000 a/m thanks to the dial made of pure iron.

All three re-creations share the same blue-gray dial that reflects the beauty of the sea but also hints at their ability to perform at depths which dim the intensity of the oceans’ blue. 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.

In addition to the limited edition trilogy, the 55th anniversary of Seiko’s first diver’s watch is also celebrated with an all-stainless steel modern re-interpretation. This new version is characterized by its slim profile and a lowered center of gravity that makes it comfortable to wear on even a smaller wrist. It features the same special 55th anniversary blue-gray dial as graces the trilogy and comes with both a stainless steel bracelet and a silicone strap. It is powered by Caliber 6R35 that delivers a power reserve of 70 hours. It will be available in a limited edition of 5,500 at Seiko boutiques and selected retailers worldwide from June 2020.