When Seiko decided to pursue 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 1978. Bearing more than a passing resemblance to the 6309-7290, the 7548-700X shares an identical case, and the bezel, insert, crown, crystal retaining ring, and crystal are all interchangeable between both styles. If the 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 version of the 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 example from April of 1980 is as good as it gets. In near NOS condition, and accompanied by the original inner box, it was built for export as is evident by the “SQ” designation on the lower dial. The dial is a flawless matte blue black with large luminous plots and well balanced text. The hour and minute hands are perfect, and the black and white reverse “lollipop” ticking off the seconds shows no chipping or paint loss. The knurled bezel rotates smoothly with a firm click in either direction, and the “Pepsi” insert is spotless. The case is crisp and unpolished, and the factory finishes are still razor sharp. The crown and case back screw down tightly, and protect the freshly serviced, hacking 7548. Portions of the original blue case back sticker still reside around the prominent Tsunami logo. It is completely original aside from a replacement mineral crystal, and is keeping perfect time. It comes attached to the original Seiko GL-831 flat vent composite rubber strap and sandblasted tang buckle. Clearly, the secret is out on these 7548 divers, and a near mint example like this is an easy addition to any roster.

Original Seiko GL-831 Flat Vent Black Composite Rubber

Serviced- 7/24

Diameter- 42mm

Lugs- 22mm