Seiko Quartz 9021-5340 – December 1985 – square, gold-colored – only 5.3 mm high – freshly serviced

5.3 millimeters in height and weighing 21 grams: This small square Seiko from December 1985 is one of the thinnest watches you can find in this price range. It disappears under any cuff – and that's exactly what it was made for.

Classification

The first half of the 1980s was the era when quartz technology truly delivered on its design potential. With no mainspring, balance wheel, or oscillating weight taking up space, cases could become as thin as mechanics had never allowed. Seiko pushed this boundary particularly far during this time, and the small rectangular dress models are the purest form of this innovation.

This particular watch operates with the caliber 9021. The case back is stamped SEIKO · BASE METAL · ST. STEEL BACK · 9021-5340 · JAPAN J along with the serial number 5D2138, which dates the watch to December 1985.

Design and Character

The gold-colored dial is finely brushed and features slender, applied baton indices at the quarter positions – nothing more is needed. The hands are equally understated, and a second hand is intentionally absent. The result is a watch that barely stands out as a timepiece on the wrist, but rather acts as a piece of jewelry.

The square case with softly rounded corners measures 25.6 × 28.3 mm with a lug-to-lug distance of 35 mm. The watch comes with a new brown leather strap with lizard embossing, which complements the warm gold tone.

Regarding case material: The case back is stainless steel, and the case itself is gold-plated base metal. This is the common construction for small dress quartz watches of these years and is appropriately marked on the case back. We expressly point this out to ensure clarity regarding the material specification from the outset. 

Condition

The watch is in very good condition and appears very high-quality. The crystal and case show only minor signs of wear.

The watch has been professionally serviced in Japan.

Technical Specifications

• Brand: Seiko
• Reference: 9021-5340
• Caliber: Seiko 9021
• Movement: Quartz
• Functions: Hour, Minute
• Case material: Gold-plated base metal, stainless steel back
• Case dimensions without crown: 25.6 × 28.3 mm
• Lug-to-Lug: 35 mm
• Height: 5.3 mm
• Lug width: 19 mm
• Weight including strap: 21 g
• Serial number: 5D2138
• Dating: December 1985
• Strap: New brown leather strap, lizard embossing
• Origin: Japan

For Whom?

For anyone looking for a truly thin watch for a suit and rejecting modern heights of twelve millimeters and above. For slender wrists. And as an entry into Japanese vintage watches at a price where you can't go wrong.

Warranty (used)

This is a used item. The limitation period for claims for defects (statutory warranty) is 12 months from delivery.

Note

As this is a used watch, no water resistance can be guaranteed. To protect the movement, the watch should not come into contact with water or moisture.