Seiko 7A28-7130

Background & History

Introduced in the early 1980s by Suwa Seikosha, the Seiko 7A28 caliber holds significant horological historical importance as the world’s first analog display quartz chronograph movement. Unlike mass-produced digital LCD modules or disposable quartz engines of its era, Seiko engineered the 7A28 with traditional horological standards. It features an all-metal, 15-jewel construction equipped with four independent micro-stepper motors, fully disassemblable architecture, and manual regulation capability.

The reference 7A28-7130 is an exceptionally rare variation within the 7A28 family. It stands out due to its striking aesthetic, pairing a stealthy black-coated case and matching bracelet with bright high-contrast gold hands and hour markers. Measuring approximately 37.5mm in diameter, the case offers a more compact, refined proportion on the wrist compared to larger sports references in the 7A28 lineup like the 7A28-7040.

The dial layout follows the classic 7A28 arrangement, featuring a 1/20th second sub-register at 3 o'clock, running central seconds at 6 o'clock, and a 30-minute chronograph totalizer at 9 o'clock. The crown is positioned at 4 o'clock, flanked by three distinct chronograph pushers at 1, 7, and 10 o'clock for start/stop, split-time, and reset operations.

CONDITION:

This Seiko 7A28-7130 is preserved in very good vintage condition. The black case finish remains sharp with only light surface scratches consistent with gentle age and careful wear. The crystal glass is completely scratch-free, offering a clean view of the matte black dial and contrasting gold hands. The movement has been fitted with a fresh battery and all chronograph functions operating as intended.

SPECIFICATIONS:
Movement: Seiko Caliber 7A28 (15 Jewels, Quartz Chronograph)

Case Diameter: 37.5 mm Case Thickness: Approx. 9.5 mm

Case Material: Black-Coated Stainless Steel

Bracelet: Aftermarket black-coated Steel Bracelet