Seiko's 6138 is the sophomore release to the 6139 and adds 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. The "bullhead" earned it's name when Seiko decided to rotate the movement 90 degrees within the case, and position the crown and chronograph pushers at the top of the case creating a resemblance to a bull's horns. At nearly 44mm, it is truly a beast, and the gradient brown dial, gold sub registers and "root beer" bezel offer an excess of 1970's appeal. This “Speed Timer” variant from May of ‘76 was specially designed for, and sold only to the Japanese domestic market. Setting it apart from its export counterpart, it bears the “Speed Timer” designation on the dial just beneath the Seiko logo, and the hands and hour markers are painted a stark flat white throughout, rather than given a luminous finish. Instead of yellow, the chronograph sweep hand is a deep fiery orange, and the day can be toggled between Japanese (Kanji) and English. Aside from a replacement crystal, it’s completely original and post service, the 6138B is keeping near perfect time. The chronograph functions are smooth and responsive, and we’ve paired it with a desert tan RAF NATO that perfectly compliments the dial. If a robust, and burly vintage chronograph with JDM credentials is on your list, this one will be hard to beat.

Clockwork Synergy Desert Tan Double Layer Two-Piece RAF NATO (clockworksynergy.com)

Serviced 7/22/18

Diameter- 44mm

Lugs- 20mm