When Seiko began development of their first core quartz diver, they didn’t have to look far for inspiration. In fact, the 6309 had only been in production for two years when the first 7548’s rolled off the production line in late 1978. Bearing more than a passing resemblance to the 6309-7290, the 7548-7000 shares an almost identical case, and the bezel, insert, crown, crystal retaining ring, and crystal are all interchangeable between both styles. And if architectural similarities were all there were, it would no doubt be a great watch by default. However, Seiko did as Seiko does, and quite literally built a quartz driven 6309 movement. With the case back removed, one look tells you all you need to know about early Seiko quartz movements. They were not plastic disposable machines to be quickly swapped out at the first sign of trouble, but beautifully, if not overly, engineered movements with jeweled pivots and precisely machined plates. Removing the dial and hands reveals a calendar and keyless works that could easily be mistaken for a 6309. Rather than cousins, these two calibres are brothers. One battery driven, and one spring driven, each as capable as they are impressive. This early JDM variant from August of 1979 would have been among the earliest examples produced. The dial is a spotless matte black with large luminous plots, and the hour and minute hands have been carried over from its predecessor. The second hand, however, is a black and white reverse “lollipop” with a large pip at the end of the tail. The bezel rotates smoothly with a firm click in either direction, and the insert shows moderate, even wear. The case is unpolished and its factory finishes are still clearly visible. The crown and case back screw down tightly with ample threading to protect the freshly serviced 7548. It offers independent quickset of both the day and date, hacking seconds, and with a fresh battery installed, it’s keeping perfect time. We’ve paired it with a “Tropic” style strap for a versatile and comfortable finish. An early Seiko first with a JDM pedigree, here’s your chance to add a Seiko diving milestone to your own roster. 

CNS “Tropic” Style Black Rubber Strap

Serviced 12/31/20

Diameter- 42mm

Lugs- 22mm