Vintage Seiko 5 Actus SS 23 jewel mechanical watch, from November 1974

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.”
In 1924 the company shortened the name to Seiko, keeping the core meaning.

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.

🕰️The Seiko Actus Line: A Legacy of JDM Quality

The Actus line was a specialized mid-range series produced by Seiko from the late 1960s through the 1970s. While the standard “Seiko 5” was marketed globally as a rugged, affordable everyday watch, the Actus was primarily intended for the Japan Domestic Market (JDM), targeting young professionals who desired a blend of style and higher-end features.
The name “Actus” is derived from the Latin word for “action” or “motion,” reflecting the active lifestyle of the era’s youth. The line is defined by three distinct characteristics:

1. The “SS” Designation: Most Actus models, including yours, carry the SS (Second Setting) badge. This refers to the “hacking” feature, which stops the seconds hand when the crown is pulled out, allowing for precise synchronization—a feature typically reserved for Seiko’s luxury King Seiko or Grand Seiko lines at the time.
2. Design Forward: Actus watches often experimented with bold case shapes, faceted crystals, and vibrant sunburst dials that pushed beyond the conservative styling of the standard Seiko 5.
3. The 5 Attributes: Despite the stylistic upgrades, the Actus remained a “Seiko 5” at its core, adhering to the five essential pillars: automatic winding, day/date display, water resistance, recessed crown at 4 o’clock, and a durable case/bracelet.

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Product Description
A masterclass in 1970s Japanese engineering, this Seiko 5 Actus SS is a collector-grade example of JDM excellence. Unlike export models, this Japan-market exclusive features the sought-after Kanji/English day wheel and the high-jewel 6106C movement.
The “SS” (Second Setting) marking on the dial indicates a hacking caliber, allowing you to halt the sweeping seconds hand for atomic-accurate time setting. The 37mm stainless steel case features a sophisticated cushion profile that wears larger than its dimensions suggest, offering a commanding presence on the wrist.
This piece comes fitted with its original signed Actus bracelet, a rarity in today’s vintage market. The silver sunburst dial catch the light beautifully, shifting from bright chrome to deep metallic grey depending on the angle.

• Condition: Fully serviced, movement regulated to within vintage tolerances. Original finish maintained.
• Movement: 23-Jewel 6106C Automatic (Hacking)
• Dimensions: 37mm diameter | 42mm lug-to-lug | 11mm thickness
• Exclusivity: Japan Domestic Market (JDM)

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Technical Specifications

• Caliber: Seiko 6106C (Automatic, Diashock shock protection)
• Jewel Count: 23 Jewels
• Vibrations Per Hour: 21,600 bph (‭‬‭‬)
• Power Reserve: Approximately 46 hours
• Mainspring: Diafix lubrication system for extended service intervals
• Calendar Mechanism: “Push-set” quickset. Pushing the crown in halfway changes the Date; pushing it deeper changes both Day and Date.
• Day Wheel: Dual-language (Kanji/English), indicative of its JDM (Japan Domestic Market) origin.
• Case Reference: 8670 (Cushion-lug design with integrated-style bracelet transition)
• Case Material: 316L Stainless Steel
• Crystal: Mineral Hardlex (proprietary Seiko hardened glass)
• Lug Width: 18mm

Watch went through a complete service by a professional watch tech and keeps good time.

Comes complete with original stainless steel bracelet included*.

(*)Note: Stock bracelets are often shortened by previous owners and may not fit you(see bracelet size in the product images). We recommend adding a new Seiko lug width matched leather strap with your order.

Modes of payment:

• PayPal
• Credit Cards (VISA, MasterCard, American Express, Discover)

We guarantee that the item in this ad looks and works as advertised and offer money back guarantee on this.

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 and Rolex are the only two watch companies considered to be 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 the 2010s, Grand Seiko and Credor were separated into fully independent luxury brands, while Seiko’s own global lineup now includes Grand Seiko, King Seiko, Prospex, Astron, Presage, and Seiko 5 Sports, with Credor remaining primarily Japan-focused.

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.