The Seiko 6139 "Pogue" automatic chronograph – a historical movement in its own right, like this full serviced mid-1970 Seiko 6139-6000 "Colonel Pogue" here, the seldom seen waterproof variant with its original H-link bracelet – was one of the first automatic chronographs created and ranks with Zenith’s El Primero and Heuer’s Calibre 11. 
 
Back in the late 1960'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 widely debated who won, but in the background of this skirmish, Seiko quietly created their own at the same time, beating the Swiss at their own game – the Seiko Ref. 6139. 
 
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 company was concentrating on the release of the world's first quartz watch, the Astron, which would completely 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.
 
We all know Omega was the first watch on the moon, mostly because Omega won’t let us forget (ever).  However, another chronograph made it to space - the more humble and less publicized Seiko 6139-6005, named after US astronaut Colonel William Pogue.  The astronaut wore his on the 1973 Skylab 4 mission - despite not obtaining NASA authorization – to time shuttle engine burns due to his familiarity with the watch and trust in its capabilities…trusting the lives of himself and fellow astronauts to the reliability of his Seiko.
 
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 6139 movement features a single register chronograph allowing time to be measured in increments of 30 minutes.
 
The transitional 6139 inhabited the a time period from 1970 through 1971 - in early 1969, the 6139 was sold with a "waterproof" signed case and dial, 6139A automatic movement, two-piece large chronograph hand, and a "notch" in the case over the crown.  However, Seiko - to comply with a U.S. legal deadline of January 1972 - changed the 6139 to feature a case and dial marked with "waterresist" nomenclature, single piece chronograph second hand, 6139B automatic movement, and no "notch" above the crown in the case.
 
In between these two 6139 models was the transitional model, like this example here, which usually (but not always) feature at least a 6139A movement, "resist" caseback, and no notch in the case above the crown - these transitional 6139 Pogue's are not common.
 
This Pogue comes with its original H-link bracelet, nylon strap, rugged travel case, and springbar tool.