Vintage Watch | Seiko Business-A 8306-8020 (Mint, Close to NOS)

Seiko Business-A 8306-8020: May 1967, Mint Silver Sunburst, Close to NOS, Fully Serviced

This Seiko Business-A 8306-8020 is fully serviced by our watchmaker in Japan, with all functions working perfectly — a May 1967 Japanese-market dress automatic in amazing mint condition, close to NOS, with a silver sunburst that still looks newly printed, a sharp one-piece steel case, and the period Seiko-signed beads-of-rice bracelet. Caseback 8306/46-8020, serial 7506367 (May 1967). Dial code at six: JAPAN 8306-8060T AD. The dial’s DIASHOCK 30 JEWELS text is what identifies this as the higher calibre 8306, not the 27-jewel 8346 that shared the same case.

The Seiko Business-A: a slim automatic for the young professional

ビジネスA — Business-A — was Seiko’s mid-1960s JDM line for the young businessman. In the 1966 Japanese range, standard Business models used the 26-jewel 6206, while Business-A received the upper mid-range 30-jewel 8306, with hand-winding as well as automatic. The line stayed in Japanese catalogues through 1968; from 1967 a 27-jewel 8346 version was also offered. The same 8306 powered the closely related Seikomatic-R at home and a handful of export Sea Lions. It was a short chapter — Seiko soon turned toward later families, including the 56-series Lord Matic — which is why a clean Business-A still feels like a find. Period ads pushed the slim profile, 薄型, designed for how it feels and how it wears. The vintage Japanese advertisement we keep in this gallery is that message, and it shows a silver sunburst Business-A very like this one.

This Seiko Business-A 8306-8020 (May 1967 · silver sunburst)

The caseback carries the classic split stamp — 8306 over 8346-8020 — because this monocoque case was tooled for both calibres, plus “ONE PIECE CASE,” “STAINLESS STEEL,” and “WATER PROOF.” Calibre 8306 is a 30-jewel automatic with hand-wind, 18,000 bph, central seconds, and day-date at 3: the date is quick-set, the day is set by moving the hands through midnight. This example is offered with a bilingual English and Kanji day wheel (the photographs show the English MON face). Published size for the 8306-8020 is 35 mm across, 42 mm lug-to-lug, and 18 mm between the lugs. Silver sunburst, applied batons, dauphine hands, and an acrylic crystal with a tension ring on this front-loading case. Presented on the Seiko-signed beads-of-rice bracelet as photographed.

Seiko Business-A 8306-8020 condition & what you receive

The silver sunburst is even and bright, with crisp BUSINESS-A and DIASHOCK printing and no obvious aging — the kind of dial that supports a close-to-NOS reading. The one-piece steel case retains sharp lugs and clean flanks; in the photographs it presents as mint, with only the lightest signs of a carefully kept life. The crystal is clear, with no obvious face scratches in the images, and the signed clasp and beads-of-rice links are tight and clean. This watch is fully serviced by our watchmaker in Japan, with all functions working perfectly. It is a strong, honest mint example — not a boxed unused set, and no papers are shown — but it is as close to new-old-stock presentation as these 1960s Business-A pieces usually come.

Read more about vintage Seiko

Want a wider view of mid-1960s Seiko dress automatics, and what to look for when you buy one? We wrote a collector’s guide on the blog.

Read the Vintage Seiko Buying Guide

Specification:

Maker: Seiko

Model: Business-A 8306-8020 (silver sunburst · dial code 8306-8060T AD · 8306/46 one-piece case)

Era: 1967 May (caseback serial 7506367)

Case Diameter: 35 mm

Lug to Lug: 42 mm

Lug Width: 18 mm

Case Condition: Mint one-piece stainless case · sharp lugs and flanks · signed crown · 8306/46-8020 · ONE PIECE CASE

Dial Condition: No obvious aging · silver sunburst · applied batons · dauphine hands · day-date at 3 · bilingual English / Kanji day (photographs show English MON)

Crystal: Acrylic with tension ring · clear in the photographs, no obvious face scratches

Movement: Cal. 8306 automatic (30 jewels, 18,000 bph, hand-wind, day-date, date quick-set) — fully serviced by our watchmaker in Japan, with all functions working perfectly,

Bracelet / Accessories: Seiko-signed beads-of-rice bracelet, as photographed

A May 1967 Seiko Business-A 8306-8020 in mint, close-to-NOS condition, fully serviced by our watchmaker in Japan, with all functions working perfectly — silver sunburst, the 30-jewel 8306, a one-piece case, and the period beads-of-rice bracelet.