Seiko's 6138 was the sophomore release to the 6139 and added a few features lacking on the former. In addition to a rolling 12 hour register for the chronograph, it could now be manually wound at the crown, and the day and date could be quick set independently. With enough design variations to suit nearly every taste, adding one to any collection is an easy decision. Adding this one however, is much easier said than done. The 7000 is easily one of the rarest and most sought after of the 6138 references. This one from December of ‘74 is only the second example I’ve had the privilege to offer, and it surely isn’t for a lack of trying. Of the few available on the open market, many are drenched in aftermarket parts, or are in less than desirable condition. To have found an original example that is as well preserved as this one was an opportunity we weren’t going to pass up. It’s “Calculator” moniker refers to the slide rule double bezel that can be used to complete any number of mathematical equations on the fly. Exactly how that’s done, could be better answered elsewhere as I’ve only managed to master some basic multiplication and division. I will offer that no matter your proficiency, it looks amazing. In addition to the outer rotating, and fixed inner bezel is a clear sliding cursor that completes the slide rule function. The matte black dial is virtually flawless and free of staining or blemishes. The luminous hour markers are whole and bear a warm patina. The sub registers are finished in charcoal gray and exhibit a subtle sunburst effect created by the tightly stacked concentric circle texture beneath the surface. The hands are free of chipping or paint loss, and the luminous windows are a uniform color. The chronograph hands are a flat fiery orange, and offer a nice contrast to the dial and sub registers. The case is unpolished, and the original circular brush finish is still intact. The coin edge bezel rotates smoothly in either direction, and the slide rule inserts are the originals showing very little wear. As the original plastic cursor was no longer attached, I made the decision to install the only worthy alternative, and now impossible to find East Tech 1:1 replacement. The 6138B is keeping near perfect time post service, and the chronograph functions are smooth and responsive. It’s completely original aside from a replacement crystal and cursor, and we’ve paired it with a black tropic that partners beautifully with the dial and bezel. A true standout, it’s sure to be a highlight in any collection. 

CNS “Tropic”Style Black Composite Rubber Strap

Serviced 12/9/21

Diameter- 44mm

Lugs- 19mm