Seiko’s iconic A239 World Timer – like the all original 1979 example here, with its original bracelet – is a great example of how a dual-layer LCD can give a watch so much more functionality at the press of a button.
The As39 was the first watch ever produced with a dual-layer LCD screen, with two LCD panels on top of one another, which it uses to show a world map. Switching between the two has the effect of completely changing the display; the first panel shows normal time and date, and the second has a world map wherein different time zones can be selected.
World Time watches, even Seiko’s own M158 (Pan Am) and A708, usually relied on having a small marker (like the size of the day indicator on many LCD watches) appear at various points around the display to indicate the time in a particular city/country/zone. The A239 went one better by putting a world map on a separate LCD, split into sections which lined up with the country or time zone being indicated.
It offered the option for a daily alarm, as well as a separate world time alarm. While it was copied/pirated and became the World Time Melody Alarm watch for low-cost distributors Armitron, Caravelle, Zeon and others its popularity never waned.
This A239 comes with its original stainless-steel bracelet, nylon NATO strap, Pelican travel case, and springbar tool – a manual for the A239 and full details of functions can be found at https://www.manualslib.com/manual/1050580/Seiko-Quartz-A239.html
1979 Seiko A239-502A World Time Quartz Alarm Chronograph
DIAL: Original Liquid Crystal Display (LCD) digital display, with all LCD portions functioning as designed.
CASE: Original 34mm (35mm w/crown) x 40mm stainless-steel case, with several small indentations on the right side.
CRYSTAL: Original crystal, with one small imperceptible surface scratch on right side (not deep).
BAND: This Seiko comes with its original Seiko-signed stainless-steel bracelet, which will fit up to an eight-ish wrist. THe bracelet instruction sticker is still partially present! This World TIme watch also comes with a nylon NATO strap, with stainless-steel hardware.
MOVEMENT: Original A239 quartz World Time movement, manufactured in November 1979. Most features - alarm, stopwatch, day & date, world time zones, etc, but sans light – work as designed.
CROWN: Original unsigned pushers.