The Seiko 6139 and 6138 series - the ever-popular, all original, and freshly serviced 1975 Seiko 6138-8020 "panda" here counts itself among the latter - were the first fully integrated automatic chronograph in the world featuring column wheel and vertical coupling mechanism. A feature of these sporty 6138-8020’s were their unique "panda" dials, hence its nickname.
With the 6138 movement, Seiko - as usual - set the standard followed by the Swiss watch industry 20 years later. The same movement configuration was adopted by Rolex when it made its own in-house movement for the Daytona in 2000, 30 years after Seiko released its 6139 and 6138 calibres. Oddly, the 6138 was the successor of the 6139 automatic chronograph movement, and produced in parallel with it until 1979.
The 6138 was technically at least equal to its Swiss counterparts, as it featured a fully integrated chronograph vice stacked modules. There were two versions of the 6138, with the first, the 6138A, introduced in 1970 with 21 jewels. The 6138B – like the one for sale here – was introduced subsequent, and featured 23 jewels. Both had a column wheel that regulated chrono functions, and a vertical clutch mechanism for engagement.
The 6138A/B was a two register chronograph, counting up to 30 minutes on one subdial and another 12 hours on the second dial. All 6138 movements feature a quick-set day/date indicator and can be handwound (unlike the 6139 model), relatively unique for Seiko chronographs of this era.
This 6138 Panda comes with a leather rally strap, nylon NATO strap, Pelican travel case, and springbar tool.
1975 Seiko 6138-8020 "Panda" Automatic Chronograph
DIAL: Original light gray/silver "linen" Seiko-signed dial, with original hour, minute, and chronograph hands - of particular note, the red tip remains on the chronograph second hand - these frequently fade to an off-yellow. Day and date function - with English and Roman numeral day variants - at the 3 o'clock position both work correctly as designed.
CASE: Original 40mm (w/o crown, 41.5mm with) x 46mm stainless-steel case. Matching original caseback. Please note this case received a machine polish at some point in its nearly half century of life, and edges are no longer sharp.
CRYSTAL: Flawless domed Seiko 6138-correct acrylic crystal, no scratches or imperfections.
BAND: This Panda comes with a black leather rally strap with white accent stitching, a rather comfortable and stylish strap that compliments this vintage Seiko 6138 Panda. This 6138 also comes with a gray nylon NATO strap, with stainless steel hardware.
MOVEMENT: Original 6128B Seiko 21-jewel automatic movement, manufactured in July 1975, which beats at 21,600 beats per hour. This watch has received a full service.
CROWN: Original unsigned stainless steel crown.