Description
SEIKO vintage mechanical watch
MADE IN JAPAN
“Seiko” (精工) is a Japanese word meaning “precision,” “exquisite workmanship,” or “refined craftsmanship.” It comes from the characters:
精 (sei) – fine, precise, refined
工 (ko) – craft, workmanship
Originally, Seiko’s watchmaking division was called Seikosha (精工舎), meaning “House of Precision.” In 1924 the company shortened the name to Seiko, keeping the core meaning.
So the brand name literally ties directly to the idea of precision engineering—which is exactly what the company wanted to be known for in its watches.
Seiko Business-A
The Seiko Business-A was introduced in late 1967 as the direct successor to the Seikomatic-R — Seiko’s slim, sophisticated dress watch for the emerging Japanese salaried professional.
The Business-A carried the Seikomatic-R’s formula forward with the refined 8306 caliber — a 30-jewel automatic with Diashock shock protection at 18,000 bph — updating the aesthetic for the new decade. The name stated the purpose plainly: “Business” for the white-collar audience, “A” for automatic. This was the dress watch of Japan’s post-war business generation.
About This Watch
This is the Seiko Business-A ref. 8306-8020, powered by caliber 8306 — 30 jewels, Diashock, automatic + manual wind. Silver/champagne sunburst dial, gold-tone baton indices, sword hands. Day-date quickset aperture at 3 o’clock. Stainless steel case with original-style steel expansion bracelet.
(*) Steel expansion bracelets are often shortened by previous owners. Check the bracelet size in the product images before purchasing.
This watch ships from 🇺🇦Ukraine with tracking number
| Brand | Seiko |
| Line | Business-A |
| Reference | 8306-8020 |
| Movement | Caliber 8306, Automatic + manual wind |
| Jewels | 30 |
| Shock protection | Diashock |
| Frequency | 18,000 bph |
| Complication | Day-date quickset at 3 o’clock |
| Case | Stainless steel, approx. 37mm |
| Crystal | Acrylic |
| Dial | Silver/champagne sunburst, gold-tone baton indices |
| Bracelet | Steel expansion (original style) |
| Country | MADE IN JAPAN |
| Era | ~1967–1970 |
CONDITION REPORT
The watch is in good vintage condition with light wear appropriate to its age.
- Dial: Light patina on the baton indices (gilded surfaces have mellowed to a warm gold tone). No moisture intrusion or major damage visible.
- Case: Light surface scratches consistent with decades of wear.
- Crystal: Acrylic — minor surface marks visible at certain angles.
- Bracelet: Intact and functional with age-appropriate patina.
Watch been through a recent service by a professional watch tech and keeps good time.
Service history prior to our ownership is unknown.
Why Collectors and Enthusiasts Want This Watch Today
The Seiko Business-A occupies a fascinating position in the vintage Seiko hierarchy — above the Seiko 5 but below the King Seiko, offering genuine 30-jewel professional-grade horology at a price the secondary market hasn’t fully caught up with.
The 8306 caliber impresses: 30 jewels when most mid-market automatics offered 17–21, with Diashock protecting the balance staff through decades of daily wear. Day-date quickset at 3 o’clock adds practical utility without cluttering the dial.
What makes this example particularly appealing is the presence of the original expansion bracelet — most Business-A watches found today have lost theirs to broken links or swapped straps. The silver sunburst dial ages naturally in the warm gold-toned way collectors prefer over polished or restored examples.
The Business-A is the one Seiko collector line that hasn’t been “discovered” yet. That window won’t stay open.
Modes of payment:
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We guarantee that the item in this ad looks and works as advertised and offer money back guarantee on this.
Seiko lug width matched leather straps: 18mm -19mm - 20mm
About the watch factory
Seiko Group Corporation (セイコーグループ株式会社), commonly known as Seiko, is a Japanese maker of watches, clocks, electronic devices, and semiconductors. Founded in 1881 by Kintarō Hattori in Tokyo, Seiko introduced the world’s first commercial quartz wristwatch in 1969.
Seiko and Rolex are the only two watch companies considered to be vertically integrated. Seiko is able to design and develop all the components of a watch, as well as assemble, adjust, inspect and ship them in-house.
Seiko offers one of the widest ranges of watch technologies in the world—quartz, kinetic, solar, mechanical, and Spring Drive—spanning everything from affordable everyday pieces to six-figure haute horlogerie. Its global lineup now includes Grand Seiko, King Seiko, Prospex, Astron, Presage, and Seiko 5 Sports.
