It is not always immediately obvious why particular complications find their way onto the mechanical wristwatch that might be viewed as indispensable, but for the air traveler, international corporate executive, news, finance, or communications personnel of the 1960’s, a watch with a 24-hour function must have carried a certain useful appeal - like all original mid-1975 Seiko 6117-6400 automatic GMT/Navigator, with original bracelet here. Even during the present day, in the era of the smart phone, there exists a certain charisma to the GMT watch that appeals to vintage watch aficionados.
The 6117 is of a similar movement pedigree to the famous Seiko 6105 diver, with the rather notable exception that the 6117 possess a date register and a third 24-hour GMT hand calibrated to the main hour hand, and an inner bezel. Turning the crown when it is in its normal depressed position controls the GMT inner chapter ring; at half-extension, the crown controls the date register; and at full extension, it sets the time.
The 6117’s independent GMT red time zone hand is used in coordination with the inner rotating bezel to tell time in another time zone of the wearer’s choice. The wearer sets the inner bezel to the time they desire (ie: GMT is four hours ahead of the U.S.’s EDT/EST, so the inner bezel is set four hours ahead of this time), and the red hand moves along with the regular hour/minute hands.
It’s important to note the red hand only makes a complete circle of the dial every 24 hours (the hour, minute, and separate time zone red hand all align at the 12 o’clock position when this occurs), so it moves more slowly than the hour hand.
This Seiko 6117 comes with its original "railroad" bracelet, dark blue and white nylon NATO strap, Pelican travel case, and springbar tool.
1975 Seiko 6117-6400 World Time GMT Automatic
DIAL: Original silver dial with red GMT hand; city names are bold and distinct (and complete!), with no fade - lume shines. Date function at 3 o’clock position works nicely. Original hour and minute hands; original inner GMT city chapter ring rotates as designed.
CASE: Original 41mm x 45.5mm stainless steel case, with original caseback.
CRYSTAL: Scratch and blemish free.
BAND: Original Seiko-signed stainless-steel "railroad" bracelet. This GMT also comes with a dark blue nylon and white NATO strap - a nice matching compliment to the blue accents on the dial of this Seiko World Time. Stainless steel hardware rounds out the NATO.
MOVEMENT: Original Seiko 17-jewel 6117 automatic movement, manufactured in July 1975.
CROWN: Original recessed unsigned stainless steel crown.