Vintage 1964 JAPAN SEIKO SPORTSMATIC5 DX 427990 23Jewels Automatic.

Vintage 1964 JAPAN SEIKO SPORTSMATIC5 DX 427990 23Jewels Automatic.

Welcome to my auction!
I am Japanese who live in Tokyo.

Item description

Movement :

• Pet name : SPORTSMATIC5 DX .
• Caliber number : 7606A.
• Movement : Automatic.
• Beat rate : 18000bph.
• Year of manufacture start : 1964's.
• Factory : Kameido.

Externals :

• Serial number : 4601279.
• Dial number : MADE IN JAPAN　42799TO.
• Glass : Acrylic.
• Case size : About 37.3mm.
• Lug width : 19mm.
• Band : New Leather Strap.

Condition :

• Used, it runs well.
• Quick set(Day/Date) : Okay.
  Set the day of the week : English only.
  Set of the date: Press the button near the 3:00 position.
  Set of the days of the week : Turn the hour hand for 24 hours to set it.
  The day difference time of an used watch is about +-1 minute / day.
• For practical, everyday use, it would be advisable to have the movement cleaned and oiled.
• There are several cracks on the case back, but they have been lightly welded on the inside.However, it's not completely sealed, so be careful not to get it wet.

Key Features

The Inaugural Founding Dawn of the Seiko 5 DX Lineage (1964): Manufactured in **1964**—the momentous year of the Tokyo Olympic Games—the **Seiko Sportsmatic 5 DX** reference **427990** represents the historic ""Deluxe"" evolution that elevated the original 1963 Sportsmatic 5 platform. Sourced in the rare pre-1965 6-digit reference numbering system, this inaugural Suwa Seikosha model introduced the ""DX"" designation, signifying premium dial finishing and over-engineered mechanical attributes for the modern executive.

The High-Grade 23-Jewel Caliber 425 (7619) Automatic Engine: Powering this historic timepiece is the elevated **23-jewel Caliber 425** (later designated as the 7619 caliber family), operating at a steady frequency of **18,000 vibrations per hour (vph)**. Equipping an early Sportsmatic with an upgraded **23-jewel movement** provided superior gear-train pivot protection, featuring Seiko's proprietary **Diashock** anti-shock architecture, Magic Lever self-winding system, and an innovative quick-set date mechanism operated via a dedicated crown button.

Architectural ""427990"" Case and Dual-Crown Integration: Sourced in a solid stainless steel case, the reference **427990** is globally distinguished for its bold, sweeping lugs and broad zero-distortion mirror-polished bevels. Designed with the main time-setting crown hidden flush at 4 o'clock and a distinct **quick-set date pusher positioned at 2 o'clock**, the case achieves a unique multi-crown silhouette engineered for maximum operational convenience.

Historic Dual-Calendar Dial Harmony and Deluxe Detailing: The dial of the **427990** showcases early-1960s executive refinement, displaying a radiant silver sunburst canvas decorated with **hand-applied, multifaceted rectangular indices**. It proudly features framed, independent day and date windows at 3 o'clock, complemented by the applied metal **""5"" shield logo**, the stylized **""Deluxe""** script, and the Suwa Seikosha factory insignia above 6 o'clock.

The Sovereign Solid Gold Dolphin Case Back Medallion: The ultimate hallmark of origin rests on the case back: the iconic **solid gold-embossed Seiko Dolphin medallion** (or deeply etched early dolphin/crown crest) set into the case center. Certifying its factory-regulated precision standard and water-resistant construction, the 1964 Sportsmatic 5 DX 427990 stands as an essential, investment-grade cornerstone reference for collectors documenting the birth of the Seiko 5 Deluxe legacy.

For more information, please look at the pictures.

Notes

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