Let's get this out of the way - there's only two watch companies with such strong reputations for making tool watches that can make patina - evidence of a life lived with the purpose that a tool watch was designed for - attractive.
 
Namely, a Swiss company that starts with an "R" and...Seiko.
 
Seiko's Ref. 6139 automatic chronograph – a historical movement in its own right, like this quite rare full-serviced 1972 Seiko 6139-6002 "Teal Sunrise" here, on a high-quality Uncle Straps SpeedTimer bracelet and with an original 1960s Seiko 5 promotional matchbox – was one of the first automatic chronographs created and ranks with Zenith’s El Primero and Heuer’s Calibre 11.
 
Seiko's 1972 Teal Sunrise 6139 chronograph is easily the most rare of the couple dozen or so variants of the Japanese watch company's famed 6139 automatics, and is frequently "Feiko'd" - in fact, at any given time, the dozen or so you can find on a certain popular online auction site are all Feiko.  Every single one of them - Feiko dial, hands, bezel, and even bracelets.
 
The easiest tell?  The Teal Sunrise is exceedingly rare due to Seiko producing it for a scant two months, in November and December 1972. If the first two digits of the case back serial number do not read "2N" or "2D", run away (or flag it to us, for our weekly #FeikoFriday Instagram posts on @DCVW_FeikoFriday).
 
Back in the 1970’s, Heuer and Zenith had taken hold of the entire sports watch industry by racing to become the first to produce an automatic chronograph.  It has been awidely debated who won, but in the background of the skirmish Seiko quietly created their own, beating the Swiss at their own game – the Seiko Ref. 6139 automatic chronograph.
 
During the early months of 1969, Seiko put the final touches on its revolutionary 6139 chronograph - in fact, the Japanese company first began putting the 6139 in automatic chronographs as early as January of the same year.
 
Seiko published its first advertisement for their new automatic 6139 chronograph in February 1969, easily beating the Swiss; however, the Japanese company was concentrating instead on the release of the world's first quartz watch, the Astron.  This watch would radically disrupt the watch world as it was known at the time (again, much to the chagrin of the Swiss watch industry, we're certain).  We possess 6139 dials dating back to November 1968, indicating Seiko beat all other rivals to produce the world's first automatic chronograph. Period.
 
The 6139 was the first chronograph to have a vertical clutch, a feature considered to be one of the hallmarks of a superior automatic chronograph movement.  The 6139 features an automatic column wheel timing control and an integrated chronograph, which means the entire movement was designed and built to be a chronograph, vice being an automatic movement with a mere timing module.  The movement features a single register chronograph allowing time to be measured in increments of 30 minutes.
 
This Seiko 6139 Teal Sunrise comes on a high-quality Uncle Straps stainless-steel SpeedTimer bracelet, and nylon strap, rugged travel case, and springbar tool.