"Business-A" – the name says it all regarding what this watch was built for: the Japanese office worker of the early 1970s who needed a reliable automatic with a full calendar and wore it every day. This example from February 1971 comes on its original bracelet and was serviced in Japan.
The Business line
Seiko's model designations in the 1960s and 1970s were programmatic: Seiko 5 stood for the robust everyday watch, Lord Matic for elevated aspirations, King Seiko and Grand Seiko for the pinnacle – and Business for the working day. The line was aimed at an audience that valued reliability and a full calendar display without the need for ostentation.
The caliber 8346 operates with 27 jewels and Diashock shock protection, displaying both the day and date. The jewel count is significantly higher than what was standard in this class, revealing the high standards Seiko applied even to its everyday lines.
The case back is stamped SEIKO · WATER PROOF · SGP BACK · ST. STEEL · 8346-8000 with the serial number 1229606, which dates the watch to February 1971. "SGP" stands for Seiko Gold Plated: the case is gold-plated, the back is stainless steel. We explicitly mention this so that the material composition is clear from the start.
Serviced
The watch was professionally disassembled and serviced in Japan in the spring of 2026.
Design and character
The champagne-colored dial features a fine sunburst finish and appears to shift between light silver and warm gold depending on the light. Applied, gold-colored baton indices with dark center grooves sit atop it—a detail that adds depth to the indices and makes them stand out from the surface. The "SEIKO" signature is at 12 o'clock, with "BUSINESS-A / DIASHOCK 27 JEWELS" below at 6 o'clock. The combined day-date window at 3 o'clock is framed in gold.
The watch is delivered on its original Seiko link bracelet with finely crafted, tapered links that continue the warm tone of the case. For a watch over fifty years old, finding the original bracelet is by no means a given—it brings the watch to 76 grams and gives it the cohesive appearance for which it was designed.
The case measures 36.5 mm excluding the crown, with a lug-to-lug of 40.2 mm and a height of 11.3 mm—compact, classic proportions that work on almost any wrist.
Condition
The watch is in good condition and the gold plating is still largely intact. The crystal is free of major scratches.
Operating note: The quick-set day and date should not be adjusted at night while the switching mechanism is engaged; set the hands to around 6 o'clock first.
Note on the crown
Manual winding via the crown feels noticeably stiffer on this watch than one might be used to with modern watches. Our watchmaker checked this during the service: the movement, winding mechanism, and crown are technically flawless; the slight stiffness is due to the delicate crown of this fifty-year-old construction and is not a defect. In daily use, the automatic movement winds itself through wrist motion, meaning the manual wind via the crown is only needed for the initial start after it has been sitting for a while.
Technical specifications
- Brand: Seiko
- Model: Business-A
- Reference: 8346-8000
- Caliber: Seiko 8346
- Movement: Automatic
- Jewels: 27 Jewels
- Shock protection: Diashock
- Functions: Hour, minute, central second, day, date
- Case material: gold-plated (SGP), stainless steel back
- Diameter excluding crown: 36.5 mm
- Lug-to-lug: 40.2 mm
- Height: 11.3 mm
- Lug width: 18 mm
- Weight incl. bracelet: 76 g
- Serial number: 1229606
- Dating: February 1971
- Service: Serviced in spring 2026
- Bracelet: original Seiko bracelet
- Origin: Japan
For whom?
For anyone looking for a vintage automatic with a full calendar on its original bracelet without needing to source a matching strap. For collectors who appreciate Seiko's model hierarchy of the early 1970s and know the Business line for what it was: the watch that was actually worn. And for buyers who prefer 36.5 millimeters in gold over a larger steel case.
Warranty (pre-owned)
This is a pre-owned item. The limitation period for claims for defects (statutory warranty) is 12 months from delivery.
Note
As this is a pre-owned watch, water resistance cannot be guaranteed. To protect the movement, the watch should not come into contact with water or moisture.
