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.”
The name first appeared on a watch dial in 1924, shortened from Seikosha and keeping the core meaning; the company itself was renamed Hattori Seiko in 1983 and Seiko Corporation in 1990.
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.
About the Business-A Line
The Business-A dial name appeared during 1967 on Seiko’s 83-series automatics, aimed at the Japanese salaried professional.
It did not replace the Seikomatic-R. The two ran side by side on the same 83-series calibers, the Seikomatic-R badge carrying the older, more formal name and Business-A the one aimed at a younger office buyer; Seiko sold several of the same case references under both. Either way the movement is an automatic with Diashock shock protection, running at 18,000 bph.
The name was deliberately straightforward: “Business” for the white-collar audience it served, “A” for automatic. No clever portmanteau — just a clear statement of purpose for the dress watch of Japan’s post-war business generation.
The 83-series calibers powering the Business-A were a genuine step up from entry-level Seiko offerings: 27 to 30 jewels when most mid-market automatics offered 17–21, with Diashock protecting the balance staff through decades of daily wear. The day-date at 3 o’clock added practical utility without cluttering the dial, with a quickset date; the day is set by cycling the hands past midnight.
The Business-A sat between the Seiko 5 below it and King Seiko above it, and still trades well under King Seiko on the second-hand market. Many were sold on period expansion bracelets, and plenty have since been swapped for straps or lost links along the way.
About This Watch
This is a Seiko Business-A day-date, reference 8306-9030, powered by the automatic caliber 8306A — the 30-jewel version of the 83-series movement, with Diashock shock protection, running at 18,000 bph. The movement is signed “SEIKO 30 JEWELS” on the rotor and “JAPAN 8306A” on the plate. Its case-back serial number, 7500470, dates its manufacture to May 1967, early in the Business-A’s run.
The dial is a silver linen finish — a fine cross-hatched texture rather than a radial sunburst — with applied baton markers, a triple-bar marker at 12 and a framed day-date aperture at 3 o’clock, the day shown in English with Sunday picked out in red. It is coded 8306-9031T, while the case reads 8306-9030; Seiko catalogued dial and case designs under separate numbers, and the shared 8306 prefix confirms the pairing. The 90xx case is one of the larger references in the line, with a polished bezel and long, faceted lugs. It comes on its Seiko-signed steel bracelet with a signed fold-over clasp.
Technical Specifications
- Brand: Seiko
- Line: Business-A
- Reference Number: 8306-9030
- Movement: Automatic, caliber 8306A, 30 jewels, Diashock, 18,000 bph
- Serial Number: 7500470
- Production Date: May 1967
- Case Material: Stainless steel
- Case Diameter: Approx. 38 mm (excluding crown)
- Dial: Silver linen with applied baton markers, day-date at 3 o’clock
- Crystal: Mineral
- Case-back: Stainless steel, engraved “Stainless Steel 8306-9030 Water Proof”
- Country of Manufacture: Japan
Condition Report
The silver linen dial is bright and clean overall, with one small brown spot at the outer edge near 1 o’clock and a few faint specks toward the rim; the applied markers and baton hands are intact. The stainless steel case is solid, the lugs keeping their definition, with light surface scratches and small marks on the polished bezel and lug edges consistent with age. The case back shows scattered light scratches, with the engraving and serial fully legible. The crystal is clear. The movement runs, the date quicksets and the day advances correctly — the day is set by cycling the hands past midnight. The Seiko-signed bracelet is complete and sound, with light wear and scratches on the clasp cover.
This watch has recently been serviced by a professional watchmaker and keeps good time.
Comes complete with original steel bracelet*.
(*)Note: Stock bracelets are often shortened by previous owners and may not fit you(see bracelet size in the product images). We match the strap to this watch’s lug width, so there is nothing for you to measure — just pick a padded leather strap for Seiko from the options at the top of the page.
This watch ships from 🇺🇦 Ukraine with tracking number
Why Collectors Want This Watch Today
The Business-A is one of the most quietly rewarding corners of vintage Seiko collecting: genuine 1960s Japanese watchmaking — a 30-jewel automatic with day-date and Diashock — at a fraction of the price its King Seiko and Grand Seiko contemporaries command. It is the same family of watch Seiko also sold as the Seikomatic-R, badged for a younger office buyer.
This one has the 30-jewel 8306A rather than the more common 27-jewel 8346A, sits in one of the line’s larger 90xx cases, and still wears its Seiko-signed bracelet. The linen finish gives the dial a texture that shifts as the light moves. For a collector who wants a period-correct Japanese automatic to actually wear rather than store, the Business-A is an inexpensive way in.
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We guarantee the item you receive looks and works exactly as advertised — or your money back.
Seiko lug-width matched leather straps — 18 / 19 / 20 mm
About the watch factory
Seiko Group Corporation (セイコーグループ株式会社, Seikō Gurūpu kabushiki gaisha), 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 is widely known for its wristwatches. Seiko is one of the few watch companies that is fully 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’s mechanical watches consist of approximately 200 parts, and the company has the technology and production facilities to design and manufacture all of these parts internally.
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. Over the decades it has launched multiple global brands, including Lorus, Pulsar, and Alba, while elevating its prestige through innovations like Spring Drive, which helped push Seiko into higher-end territory. In 2017, Grand Seiko was spun off into its own standalone luxury brand, while Credor remains part of Seiko’s own lineup, sold primarily in Japan. Seiko’s own global lineup now includes Grand Seiko, King Seiko, Prospex, Astron, Presage, and Seiko 5 Sports.
Among Seiko’s key lines, Seiko 5 (born in 1963) is the gateway mechanical series known for durability and value; Lord Matic defined 1970s style with faceted crystals and colorful dials; Astron remains Seiko’s flagship GPS-solar tech line; Presage focuses on traditional mechanical craftsmanship with enamel and urushi dials; and Prospex delivers professional-grade dive, field, and pilot watches often embraced by enthusiasts. At the top end, Grand Seiko emphasizes precision, Zaratsu polished design, and movements like Spring Drive, while King Seiko—revived in the 2020s—brings back sharp, elegant 1960s styling with modern calibres.
Finally, Credor represents Seiko’s pinnacle of artisanal watchmaking, producing low-volume pieces in precious metals and showcasing Japanese decorative arts and haute complications from the Micro Artist Studio. Beyond watches, Seiko has also produced various electronic devices and, historically, jewelry and eyewear—though those divisions have since shifted to other companies.
