It’s 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.
Even during the present day, in the era of the smart phone, there exists a certain charisma to the GMT/Navigator watch – like this 1970 Seiko 6117-6400 automatic GMT here, on its original bracelet – 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.
At the end of 1969, Seiko started production of the next series of mechanical World Time GMTs, following its popular 6217 GMT designed for Japan hosting the 1964 Olympic Summer Games. It was a complete redesign, including a new case and crown, new bracelet, new dial finishes, new handset, and updated bezel. The newly designed automatic movement, the 6117B, now included hacking seconds.
Turning the 6117 GMT's crown 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 GMT comes on its original bracelet, and with nylon strap, rugged travel case, and springbar tool.
1970 Seiko 6117-6400 World Time GMT Automatic
DIAL: Seiko-signed dial with red GMT hand; city names are crisp and legible, with little fade. Date at 3 o’clock position works as designed. Matching hour and minute hands; inner GMT city chapter ring rotates as designed, with none of the lettering smears on lessor, more common examples.
CASE: Stainless-steel case measures 41.5mm x 45mm, with matching caseback.
CRYSTAL: Seiko 6117-correct domed crystal, scratch and crack free.
BAND: This Seiko 6117 comes on its original signed stainless-steel bracelet, which will fit up to an approx. 7.5 inch wrist; this GMT also comes with a light blue, red, and white nylon strap.
MOVEMENT: Seiko 17-jewel 6117 automatic movement, manufactured in June 1970. Movement hacks, as designed.
CROWN: Unsigned stainless-steel crown, mostly recessed.