The Seiko 6139 automatic chronograph – a historical movement in its own right, like this incredibly rare Japanese Air Self-Defense Force (JASDF) fighter pilot-issued 1973 Seiko 6139-7012 SpeedTimer "Military" automatic chronograph here, on its original Seiko bracelet – was the first automatic chronograph created, and ranks with Zenith’s El Primero and Heuer’s Calibre 11.
 
The best thing about these made in Japan-only Seiko 6139-701x's? They feature atypical Arabic numerals counting the hours - Seiko used this design sparingly during this era, and it gives the watch a great military stance.
 
And it appeared the Japanese military, in the form of the Japanese Defense Forces, agreed - these were issued to the JDF navy (JMSDF) and air (JASDF) forces; issued examples are exceedingly rare, and feature military insignia on the case back and JDF in Kanji Japanese.  A 1981 Japanese TV special, "The Last Show," highlighted JASDF pilots and their U.S.-provided F-86 Sabre and Mitsubishi T-2 fighter jets.
 
The interviews revolved around the JASDF aerobatic flying squad (akin to the USAF Thunderbirds and Navy Blue Angels), the Blue Impulse, and their lengthy use of the F-86 Sabre before transitioning to Mitsubishi T-2's.
 
And on the pilot's wrist?  The Seiko 6139-701x, naturally.
 
And this is one of those exact watches, issued to JASDF fight jet pilots - this is easily the most rare 1970s Seiko 6139's ever made, period.  We've written about one of this JASDF-issued watches in depth, here.
 
Intriguingly, whereas a normal 6139 would feature its serial number on the case back, on JASDF and JSDMF-issued examples it was instead inscribed on the inside of the case back, strongly indicating the watch was a unique one special ordered by JASDF from Seiko.
 
There was a second unique 6139-701x ordered by the Japanese Maritime Self-Defense Force, which featured the JMSDF name, anchor insignia, and same military personnel serial number on the case back. Both the JASDF and JMSDF watches were seemingly issued for only two years.
 
On Seiko's revolutionary 6139 calibre itself, 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.
 
This JASDF fighter jet pilot-issued 1970's Seiko 6139 "Military" comes on its original stainless-steel Seiko bracelet, and with nylon strap, rugged travel case, and springbar tool.