Seiko unveils two new models within the Prospex Marinemaster line—one of which is made in collaboration with the Japan Agency for Marine-Earth Science and Technology (JAMSTEC)
Japan’s relationship with the sea and waves is a profound one, easily observable across its art, cuisine and deep-seated traditions. In this regard, Seiko is no different. Their first diver’s watch, made in 1965, was the self-winding 150M, which accompanied members of the Japanese Antarctic Research Expedition to the South Pole from 1966 to 1969.
Decades later, this intrepid attitude has not faltered. The brand’s longstanding partnership with the Japan Agency for Marine-Earth Science and Technology (JAMSTEC), which began in the Eighties, has resulted in a collaborative piece in one of two new timepieces joining the Prospex Marinemaster line.
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Above The HBF002 leaves an icy trail in its wake (Photo: courtesy of Seiko)

Above The HBF002 reflects Seiko's longstanding partnership with JAMSTEC (Photo: courtesy of Seiko)

Above The caseback is marked with “JAMSTEC” (Photo: courtesy of Seiko)
Revisiting the 300m Marinemaster line, the HBF002 collaboration model (limited to only 1,000 pieces) is visually stunning. The pebble-textured dial features a vertical-oriented gradient, which emulates an icebreaker leaving in its wake a frozen trail. At the centre is a deep blue hue, which gradually lightens as it approaches the sides of the dial. This is accentuated by the ceramic bezel, which has been coated in a similar shade. This watch’s arrival is timely: the Mirai II (mirai meaning future), Japan’s first icebreaker with research-ready capabilities, is expected to be completed this year.

Above The HBF001 sports a classic black dial and Marinemaster look (Photo: courtesy of Seiko)
The HBF001, on the other hand, is a diver’s watch in its purest form. The dial’s black hue and fine-grain texture is complemented by a similarly coloured bezel. Visibility remains crystal clear, thanks in part to the indices’ bezeled edges and the design itself, which minimises the reflection of light.

Above The updated clasp design present on the HBF001 and HBF002 (Photo: courtesy of Seiko)
Aesthetics aside, these watches are mechanically identical inside. Both are powered by the automatic Calibre 8L45, one of Seiko’s finest movements and a first for the collection. It offers a 72-hour power with an accuracy of +10 to -5 seconds. The mainspring and hairspring are made out of the brand’s proprietary Spron alloy, greatly enhancing durability and robustness. The crown, too, has been slightly adjusted—instead of being screwed directly into the case, it is set onto a separate component entirely, making it much easier to replace and maintain. One more notable change (and much-appreciated convenience) is the updated clasp, which allows for easy adjustments from up to 16mm in 2mm increments.
These new entries uphold the adventurous spirit so intrinsically linked with Seiko’s Prospex Marinemaster line. Whether you intend on exploring the depths of the sea, or planning your own trip to the world’s most frigid locations, both are built to withstand the journey.
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