Baselworld 2018: Seiko Celebrates the 50th Anniversary of the ref. 6159-7001 With Two Hi-Beat Divers, ref. SLA025 and SLA019

2018 marks the 50th anniversary of the release of Seiko’s landmark 6159-7001 dive watch. It was the Japanese firm’s first hi-beat diver, and it featured a beautiful monocoque case, screw down crown, Hardlex mineral crystal, unidirectional bezel, and a depth rating of 300 meters. It was arguably the best-engineered dive watch available in 1968, and it’s a highly sought-after vintage piece today.

To celebrate this anniversary, Seiko is putting out two limited editions—introducing the reference SLA025, and extremely faithful recreation of the historical model; and the SLA019, a watch our editor has dubbed “The Green Marine.”

What can I say? Seiko’s done it again.

I’ll begin with the the SLA025. Since last year’s incredibly well-received SLA017 (62MAS recreation), Seiko diehards have been excitedly anticipating this release. There have already been several releases based on the 6159 (the ref. SBDX001 Marine Master, for one), but the SLA025 is by far the most faithful reproduction yet.


The shape of the case here is nearly identical to that of the original, but it’s been scaled up to 44.8mm in width and 15.7mm in height. Like its inspiration, the SLA025 is monocoque with a flat back. As far as finishing goes, this big chunk of steel gets Seiko’s highly specialized Zaratsu polishing treatment, which gives its edges an incredible sharpness that one generally sees in watches from Seiko’s most premium ranges. This watch is basically a Grand Seiko in a proverbial diver’s wetsuit.

The dial is a near exact reproduction of the 6159, from its applied and lume-filled golden hour markers all the way down to the gilted dial text. The hands are also more faithful to the original, and include the classic “stop-light” second hand tip with the red lume dot. The crystal has been upgraded from Seiko’s proprietary Hardlex mineral glass to a double-domed sapphire crystal with AR coating.

True to the original 6159, the SLA025 incorporates a real 36,000bph hi-beat movement—the 37-jeweled caliber 8L55. This is essentially a Grand Seiko movement without the finishing, and according to Seiko it was specifically designed for the diver’s use. It is made and assembled by the specialized craftsmen and women in the Shizukuishi Watch Studio in Northern Japan. In 1968, the 36,000 bph movement was cutting edge, and it remains so today, delivering exceptional accuracy and a power reserve of 55 hours.The SLA025 will be supplied only on a silicone strap that is a reproduction of the original Seiko “waffle” band, and it will be limited to an edition of only 1,500 pieces. Priced at approximately $5,400, it is definitely on the pricier side of things, but you have to remember that this really is a Grand Seiko in disguise—and a what a disguise it is.

The SLA019, on the other hand, is a different breed of homage. Instead of being a 6159 recreation, it is instead an updated version of the current SBDX017 Marine Master. The big kicker with this one are the rich green-colored dial and bezel, which is definitely an unexpected and delightful twist.

According t Seiko, the green color is meant to reflect the “lush tones of the ancient cedar trees on the island of Yakushima at the southern end of the Japanese archipelago.” This is a World Natural Heritage site, and it’s an area that is a popular dive destination in Japan.

Whatever the inspiration, the “Green Marine” is a killer watch with some solid specs. The bezel gets an upgrade with a zirconia ceramic insert for better scratch resistance. The 5, 10, 15 and 20-minute markers are done with a specially vibrant LumiBrite compound for increased legibility. Even the case gets an upgrade with a “super-hard” coating for added durability.This one will have the same 26-jewel caliber 8L35 automatic movement as past iterations of the Marine Master. It has 50 hours of power reseerve. Although it’s not a hi-beat movement, it is still at its core an undecorated Grand Seiko caliber.

The SLA019 will come with the excellent standard Marine Master bracelet upgraded with the same “super-hard” coating as the case, and it will also be paired with a silicone strap. Limited to 1,968 pieces, the SLA019 is priced lower at $3,250. Seiko

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Christoph (Instagram’s @vintagediver) is a long time collector and lover of all things vintage, starting with comic books when he was a kid (he still collects them). His passion for watches began in 1997 when he was gifted a family heirloom vintage Omega Genève by his step-father. That started him on the watch collecting path—buying and selling vintage watches of all sorts, with a special appreciation for vintage dive watches and Seiko.