Vintage Seiko Business-A 8346-9010, 27 Jewels Automatic JDM, from April 1967

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.

🕰️ Seiko Business-A overview

The Seiko Business-A line occupies a fascinating “lost chapter” in Seiko’s history. While the Seiko 5 became a global icon and the Grand Seiko reached for the stars, the Business-A was a short-lived but technically impressive series specifically designed for the rising Japanese “salaryman” class of the late 1960s.

Business-A line was created as a “Premium Daily” watch, had a notably brief and specific production window, primarily spanning from 1967 to 1969.

It served as a bridge while Seiko was moving away from the older, thicker automatic designs of the early 60s toward the high-beat, ultra-slim movements of the 1970s. Because the Lord Matic replaced it so quickly, the Business-A ran for only about three years — a short window next to long-running lines like the Seiko 5.

Comparison: Business-A vs. Seikomatic-R

You will often see the Business-A compared to the Seikomatic-R. They are essentially cousins:

• Seikomatic-R: Aimed at an older, more established demographic (more gold plating, more conservative dials).

• Business-A: Aimed at the “younger” generation (stainless steel, sharper lines, bolder dial markings).

Product Overview

This Seiko Business-A (8346-9010) is a definitive example of 1960s Japanese executive style. Positioned as a sophisticated mid-tier offering during Seiko’s golden era, the Business-A line was marketed toward the “rising professional” class, offering a higher jewel count and a more finely finished movement than the standard Seiko 5 series.

Produced in April 1967, this specimen features the refined 8346A movement, a 27-jewel automatic built by Suwa Seikosha, beating at 18,000 vph with hand-winding and Diashock shock protection.

Key Features & Condition:

• JDM Exclusive: This is a true Japanese Domestic Market (JDM) model, featuring a Kanji-only day wheel, adding a layer of regional authenticity for collectors.

• Movement: Caliber 8346A Automatic with hand-winding capability. 27 Jewels, 18,000 vph, Diashock shock protection. Built by Suwa Seikosha.

• Dial: Silver sunburst dial with applied baton indices. The dial is in very good vintage condition for its age, with light speckling visible near the outer edge under close inspection, and sharp “Business-A” and “Diashock 27 Jewels” text.

• Case: Stainless steel case, approx. 37–38 mm excluding crown — one of the larger-cased references in the Business-A line. The “Water Proof” and “Stainless Steel” engravings on the case back are deep and clearly legible (Serial: 7426199).

• Hands: Polished faceted baton hands with a slim sweep seconds hand.

Technical Specifications:

• Brand: Seiko

• Model: Business-A

• Reference: 8346-9010

• Caliber: Seiko 8346A (Suwa Seikosha)

• Movement: Automatic with hand-winding

• Jewels: 27

• Frequency: 18,000 vph

• Year: 1967 (April) — serial 7426199

• Day/Date: Kanji day and numerical date in a single window at 3 o’clock

• Case Material: Stainless Steel

• Case Diameter: Approx. 37–38 mm (excluding crown)

• Crystal: Acrylic

• Bracelet: Vintage steel bracelet, unsigned clasp

• Service History: Recently serviced by a professional watch technician

Collector’s Note: The Business-A ran for only about three years before the Lord Matic and its 56xx movements took over Seiko’s mid-range, so the line marks a short, well-defined chapter in Seiko’s late-1960s output. This example pairs one of the larger cases in the range with a freshly serviced 83-series movement and a JDM kanji day wheel — a straightforward, honest daily-wear vintage Seiko rather than a shelf piece.

This watch has recently been serviced by a professional watchmaker and keeps good time.

Comes complete with vintage 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.

Modes of payment:

• PayPal
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• bitcoin

We guarantee the item you receive looks and works exactly as advertised — or your money back.

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.