Seiko 5 6309-6020 Men’s Dress Automatic Vintage Watch 1980

An inner 24-hour track distinguishes the matte black dial of the Seiko 5 watch from 1980, reference 6309-6020. Its compact steel tonneau case measures 35 mm across and 39 mm lug-to-lug, framing luminous-accented silver indices and a date window at 3. A black NATO strap replaces the original steel bracelet, giving the original head a more casual attachment.

Matte black dial and 24-hour notation

Applied silver-tone baton indices have luminous accents. Inside them, a 24-hour track supplies an additional hour-reading scale without adding another hand. A framed date window sits at 3.

The hour and minute hands are slim batons with luminous inserts. A long central seconds hand sweeps across the dark face, keeping its proportions balanced with the narrow markers and inner track.

Short tonneau span and black NATO

Brushed surfaces and polished transitions define the stainless steel tonneau case. Its 35 mm width and 39 mm lug-to-lug span keep the head small and discreet. The recessed crown at 4 stays close to the outline.

The current black NATO strap replaces the steel bracelet of the original configuration. It introduces a casual attachment around the dress watch’s compact head while leaving the original dial, hands and case intact.

Caliber 6309 and automatic operation

The automatic watch uses Seiko caliber 6309, which has 21 jewels and operates at a model beat rate of 21,600 vibrations per hour. It does not support manual winding or hacking. It winds automatically during wear, and the seconds hand continues running during time setting.

The 6309 family was used in both dress and diving watches, while this example has the compact proportions and restrained face of the dress range. Its inner 24-hour scale is a dial-reading aid, alongside the ordinary date display.

The watch is in excellent used condition, fully serviced and fully operational. Its original dial, hands and case remain with the disclosed replacement NATO strap. A 12-month warranty is included, and worldwide shipping is available.