From the authentic sports watch brand Seiko Prospex, a limited-edition collection of three models commemorating the 55th anniversary of Seiko Divers, along with a trilogy collection box containing all three, is scheduled for sequential release in Japan and overseas from May to August 2020.• Subject to change

Seiko Prospex is a brand of authentic sports watches equipped with professional functions for sports and outdoor activities such as diving and trekking. Among them, the diver's watch, which symbolizes the brand, was born in 1965 as the first Japanese-made diver's watch, and has since introduced a succession of epoch-making watches equipped with unique technologies.

With over 50 years of continuous evolution, it has earned high praise and trust from professional divers and adventurers worldwide. Furthermore, Seiko has always been a pioneer in diver's watches, leading the world, as evidenced by its significant contribution to the establishment of JIS (Japanese Industrial Standards) and ISO (International Organization for Standardization) diver's watch standards, which were based on the performance standards that Seiko has used as a benchmark for technological development.

The evolution of Seiko's diver's watches can be said to be the history of Japanese-made diver's watches itself. The first Japanese-made diver's watch announced by Seiko in 1965 is known to have been donated as equipment for the Japanese Antarctic Research Expedition four times starting in 1966. The 300-meter air diving model with a world-leading 10-beat high-beat movement announced in 1968, and the 600-meter saturation diving model that adopted the world's first titanium case for a diver's watch in 1975, have also proven their reliability by accompanying divers and adventurers on numerous expeditions to extreme environments.

In 2020, marking the 55th anniversary of its birth, three special anniversary models befitting its history of innovation have been announced. This is a limited-edition collection based on historical models from 1965 to 1975, which are milestones in Seiko's diver's watch history, updated with specifications and designs worthy of the 55th anniversary.

The most distinctive feature of this collection is the adoption of "Ever-Brilliant Steel," a stainless steel material with the world's highest level of corrosion resistance, for the case. This material possesses both superior corrosion resistance to stainless steel used in conventional luxury watches and a beautiful white luster, making it the first material of its kind to be used for a watch case. Previously, this material was used for equipment exposed to chloride-containing environments (environments exposed to seawater or industrial chloride ions), such as marine structures and chemical/food processing plants, and it was considered difficult to meet the quality requirements for accessories like watches. However, by overcoming these challenges, Seiko has succeeded in practical application, viewing it as a fitting endeavor for the culmination of 55 years and further evolution towards the future of Seiko's diver's watches.

Furthermore, this collection features "blue-gray" as its key color. This hue expresses the beauty and mystery of the deep sea, which loses light as depth increases, inviting one into an unknown world, through the colors of the dial and strap.

The "1965 Mechanical Diver's Reissue Design" is a model that pays homage to the original model launched in 1965 as the first Japanese-made diver's watch, which marked the origin of Seiko's special watch development. It faithfully reproduces the original design as much as possible, using a reinforced silicone material to recreate the TROPIC rubber strap with a fabric-like texture that was originally paired with it.

The movement is meticulously crafted at the Shizukuishi Watch Studio, which handles everything from parts manufacturing to final assembly. It features the "8L55" mechanical high-beat caliber, specifically designed for diver's watches, which achieves stable accuracy through its high-speed vibration of 36,000 beats per hour (10 beats per second). This results in a watch that combines aesthetic appeal and durability befitting a modern luxury timepiece.

The "1968 Mechanical Diver's Reissue Design" is based on the groundbreaking diver's watch announced in 1968, which uniquely housed a 10-beat high-beat movement, then the world's highest standard, within a 300-meter water-resistant case featuring a monobloc construction without a separate case back. In 1970, mountaineers Naoki Uemura and Teruo Matsuura of the Japanese Alpine Club carried this model on their Everest ascent, proving its high reliability. Today, alongside the model with a protector, it is considered synonymous with Seiko's diver's watches.

Not only has the water resistance, which was for air diving at the time, been upgraded to saturation diving specifications, but by adopting Ever-Brilliant Steel for the case and equipping it with the modern 8L55 mechanical high-beat caliber, similar to the "1965 Mechanical Diver's Reissue Design," this anniversary model surpasses the reissue model that won the "Sports" category at the Grand Prix d'Horlogerie de Genève in 2018.

The "1975 Mechanical Diver's Reissue Design" is an updated model of the 600-meter saturation diving diver's watch that was born in 1975, prompted by a letter received from a professional diver living in Kure City, Hiroshima Prefecture. The letter stated that "current commercially available diver's watches cannot withstand saturation diving systems using high-pressure helium-mixed gas as breathing gas for deep-sea dives beyond 300 meters." In response, a development project team was formed to provide a perfect solution. After years of research and development, the world's first 600-meter saturation diving diver's watch with a titanium case was completed in 1975.

This innovative model, which incorporates a titanium protector in the outer part of the dual-structure case, boasts world-leading watertightness, airtightness, and durability, including corrosion and scratch resistance. It features 23 unique technologies (patents, utility models, design registrations) not only in the case but also in the accordion-style polyurethane strap designed for underwater wearability and safety. This model utilizes a ceramic protector, Ever-Brilliant Steel for the bezel, and a pure iron dial, achieving magnetic resistance of 40,000 A/m, exceeding JIS standards for magnetic resistance type 2, thus realizing specifications befitting a top-tier professional tool.

In this collection, prior to the release of individual models, a "Trilogy Collection Box" will be available in a limited quantity of 100 sets, starting May 22, 2020. This special box, designed to evoke a diver's watch submerged in the deep sea, includes all three models with unified serial numbers on the case backs, along with optional straps in different colors for each model.• Subject to change

This is a rare set that further enhances the special feeling befitting the 55th anniversary.

Alongside the release of the reissue designs, the "1965 Mechanical Diver's Modern Design" model, based on the 1965 mechanical diver's watch, has been renewed. With a more comfortable fit and a slimmer case shape than previous models, it offers enhanced versatility for a wider range of occasions. Like the reissue design collection, this is a limited-edition model featuring a blue-gray dial, the key color of the anniversary models, and comes with an optional strap in reinforced silicone matching the dial color.