There are numerous vintage Seiko divers popular with collectors, but few more so than the legendary (and rare!) 6306 ScubaPro 450 series - like this 1977 Seiko 6306-7001 ScubaPro 450 automatic diver here.
Between 1965 and 1975, Seiko brilliantly conceived, designed, and produced three generations of classic ISO-certified 150 m divers’ watches, in chronological order - the 62MAS, 6105-8000/9, and the 6105-8010/9.
Then 1976 arrived...
That year, Seiko debuted its replacement for its 6105, conceived in two different specifications - one for the domestic Japanese Domestic Market and the other for overseas. The latter international variant - the 6309 - featured a 17 jewel 6309A automatic movement, fitted with bilingual day wheels appropriate for the target geographic it would be sold in, while the former Japan domestic version - the 6306 - was to be fitted with a more advanced 21 jewel 6306A movement, with hacking and an English/Kanji Japanese day wheel.
The 6306 lived a rather short life in between the 6105 and 6309, and was produced from 1976 to 1981, when Seiko would favor the 6309 until it too was replaced with the 7002 diver in 1988. The 6306 and 6309’s were a successful effort by Seiko to improve the 6105 movement, which allowed for greater lifespan, robustness, and ease of maintenance.
Both were popular with the U.S. military, akin to the Seiko model it replaced, the 6105 - its (much more expensive) forefather - and quickly became the staple of the working diver. Seiko also teamed up with legendary diving company ScubaPro to make a quite limited run of ScubaPro-branded 6306's, by most accounts approximately 1,000.
A true grail watch, the ScubaPro 450 was part of a marketing agreement between Seiko and the diving firm; with that said, the changes were mostly surface in nature and limited to the signed dial and unique rubber strap. Often "feiko'ed," the ScubaPro 450 dials received a unique dial code: 700L T to 700J T, and were produced from circa early 1977 through late 1978/early 1979 - making the example here one of the first to be made.
Per ScubaPro, the company is "the world's most iconic brand of dive equipment, built by and for those whose passion is found below the water's surface. Founded in 1963 by Gustav Dalla Valle and Dick Bonin, SCUBAPRO remains the industry's gold standard for innovation, performance, reliability and durability."
This Seiko 6306 JDM diver comes on a Seiko DAL1BP rubber strap, and with nylon strap, rugged travel case, and springbar tool.
1977 Seiko 6306-7001 ScubaPro 450 JDM Automatic Diver
DIAL: Black Suwa-signed dial with UV-fade, rendering the "Water Resist" lettering a yellow-ish color (from the original red), along with the quite unique "ScubaPro 450" nomenclature front and center, along with dial codes unique only to these rare ScubaPro dials. The 6306 dial has a deep bevel on the day/date window (a correct indicator of a genuine dial) - yet another indicator of legitimacy, the ScubaPro 450 dial font is a slightly lighter shade of white than the rest of the dial. English/Kanji Japanese language variants on the day wheel. Correct hour, minute, and seconds hands - lume shines following exposure to bright light, with a light lume patina throughout the dial and hands.
BEZEL: Bi-directional and ratchets with a click as designed; bezel insert is in good condition, with little wear - impressive given the age of the watch. These inserts are normally first to be damaged when these diver's were used as designed, ie: hard.
CASE: Stainless-steel cushion case measures in at a hefty 44mm (w/o crown, 44.5mm with) x 45mm, with brushed finish remaining on case top and sharp case lines. Matching caseback, with its Seiko "wave" emblem crisp and defined.
CRYSTAL: Seiko 6306-correct Hardlex crystal, no cracks or scratches.
BAND: This 6306 comes on a Seiko DAL1BP rubber strap, paired with "fat boy" springbars; it also comes with a leather-backed olive-drab green canvas strap and beige, grey, and white nylon strap.
MOVEMENT: Seiko 6300-series automatic movement, 21 jewels, manufactured in January 1977.
CROWN: Screw-down unsigned stainless-steel crown operates as designed.