6159-7001 Seiko Hi-Beat Professional 300m

If you think the depth and breadth of vintage marques like Universal Genève or Enicar are strong, they are. And yet, neither really hold a candle to the world’s longest running vertically-integrated manufacture outside Switzerland. Seiko has made more dive watch offerings than I will ever be able to hold in my head. Despite that, I can state with confidence that the 6159-7001 is among my top five for its vintage yet durable charm, GS-derived hi-beat, uniquely Japanese one-piece case profile, and ultra-legible dial.

Seiko’s first 300m was a landmark. Five years after the 62MAS, on the heels of the 150m 6215, Seiko released this beauty. The 6159 was Seiko’s first monocoque 44mm case design with a screw down crown. This was a new high, or rather low depth, for the brand—and an innovation within dive watches generally. This design may not have been their first diver, but it was a massive leap in engineering and design. This 6159 set a blueprint for every turtle, SKX, and Prospex you love today.

It seems that Seiko got carried away a little here. Not only was its monocoque case a first, but they had a new bulletproof caliber. Seiko fitted the case to their cal 6159A, which was a 36000 vph hi-beat movement originally intended for their new Grand Seiko line. It was one of their first automatic calibers that could also be manually wound. The hands are all thicker than the previous 6215 with wider lume plots for increased visibility. The watch was only produced for 1968 and 1969, making it one of the rarest high-production models in Seiko’s vintage history. This is watch you want to buy carefully, as almost all parts of its movement and case are not shared with any other models.

Interest in the 62MAS and many recent reissues has meant that the market for original early Seiko divers has been steadily drying up in the last few years. This example has the kind of case I love to see, where it has clearly been used but retains factory lines and seemingly not yet introduced to a polishing wheel. That patina is matched on the crystal. Its dial shows no significant damage and still has original tritium applications on the plots and handset. It comes from a well-regarded Miami retailer.

Find this 6159-7001 here from Menta Watches for 6000 USD.