Seiko's legendary 6309 is best known for the used of the automatic movement in its so-called sizable "turtle" - aka the 6309-7040/9 - dive watch (in particular, after Seiko re-released it under it's Prospex line). However, Seiko placed its 6309 automatic movement in a number of lesser known dive watches - like the 1979 Seiko 6309-8360 automatic diver here, on it original stainless-steel Seiko dive bracelet.
Crowned by Watches of Espionage (WoE) as "One of history’s most important diving & military watches," the 6309 was popular with the U.S. military (not to mention militaries further afield from the U.S., as well), akin to the Seiko model it replaced, the 6105 - its much more expensive forefather. After it's debut, the Seiko 6309 quickly became the staple of the USMIL (both regular forces and Special Forces) and commercial divers everywhere. U.S. Navy Naval Special Warfare units - aka Navy SEALs - favored Seiko divers, in particular the 6309.
"Not limited to official issue, the 6309 was also commonly purchased by military members at the local PX or Navy Exchange. In past profiles of special operators, which are extensive at this point, the 6309 is easily the most commonly encountered mechanical dive watch in the late 70s and 80s. When U.S. Navy SEAL Dave Hall shook hands with Scout Sniper legend Gunny Carlos Hathcock after completing sniper school, a Seiko Turtle was on his wrist. When Jose Gordon was a young Army Ranger assisting the Contras in their fight against communism in Nicaragua in the 1980s, he wore a Seiko 6309."
Seiko's 6309 (and its Japan-only 6306 sibling) dive watch was the Japanese watch manufacturer's third generation of recreational/professional divers. The 6309 replaced the 6105 in 1976, and was produced until 1988, when Seiko replaced it with the 7002 diver. The 6309 was a successful Seiko effort to improve upon the 6105 movement, which allowed for greater lifespan, robustness, and ease of maintenance – not to mention they look great on the wrist.
The Seiko 6309 diver comes on its original stainless-steel Seiko bracelet, and with nylon strap, springbar tool, and rugged travel case.
