The Seiko 6139 automatic chronograph – a historical movement in its own right, like this recently serviced 1969 Seiko 6139-6010 SpeedTimer "Deep Blue" automatic chronograph here, on its original stainless-steel SpeedTimer "railroad" bracelet - was one of the first automatic chronographs created and ranks with Zenith’s El Primero and Heuer’s Calibre 11.  
 
Seiko did their homework when they designed these deep blue dials, and pictures do not do these justice.  These dials are simply amazing to behold in person, and this dial - with its sugar cube-like lume - is no different. 
 
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 widely debated who won, but in the background of this skirmish, Seiko quietly created one theirs 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.
 
The 6139 was the first chronograph to have a vertical clutch, a feature considered by many to be one of the hallmarks of a superior automatic chronograph movement.  The 6139 features a single register chronograph allowing time to be measured in increments of 30 minutes, and also features an automatic column wheel timing control, vertical coupling mechanism.
 
Seiko's innovative design featured an integrated chronograph – the first in the world – which means the entire 6139 movement was designed and built to be a chronograph, vice being an automatic movement with a mere timing module added.
 
With this movement, Seiko set the standard, which was followed by the Swiss watch industries 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 the caliber 6139 and 6138.
 
This Seiko 6139 SpeedTimer comes on its original stainless-steel Seiko SpeedTimer bracelet, and with nylon strap, springbar tool, and rugged travel case.