Description
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.”
The name first appeared on a watch dial in 1924, shortened from Seikosha and keeping the core meaning; the company itself was renamed Hattori Seiko in 1983 and Seiko Corporation in 1990.
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.
About the SKX Mid-Size Diver-Style Line
When Seiko replaced the long-running 7009 with the calibre 7S26 in the mid-1990s, it rebuilt its whole affordable sports range around the new movement. The best known result is the 200 m SKX007/009 — but alongside it Seiko built a smaller, lighter, 100 m-rated family on case reference 7S26-0050: the SKX021, SKX023, SKX025 and SKX027. Mechanically the four are the same watch; they differ only in dial colour, hand finish, and whether they left the factory on a bracelet or a rubber strap.
At roughly 37 mm across, the 0050 case is a genuinely mid-size watch — some five millimetres narrower than the SKX007 — and it wears closer to a 1960s sports watch than to a modern diver. The 10 bar rating places it honestly in the dive-styled sports category rather than the professional diver’s class: no ISO certification and no 200 m marking, but the same screw-down crown, unidirectional bezel, Hardlex crystal and screw-down wave-medallion case-back. Seiko kept the mid-size references in the catalogue into the 2000s, and the SKX range as a whole was discontinued in 2019.
About This Watch
This is the black-dial, steel-bracelet member of that family — case reference 7S26-0050, catalogued by Seiko as the SKX023. The case-back serial 382665 reads as August 2003: the leading digit gives the year’s last figure and the second digit the month, and on a 7S26 case a “3” can only be 2003, since the calibre itself did not appear until the mid-1990s.
The dial is glossy black with applied luminous markers — round plots around the chapter, a broad triangle at 12 and batons at 6 and 9 — printed WATER 10BAR RESIST and 21 JEWELS above six, with MADE IN JAPAN and the 7S26-0050 code at the foot. The day-date sits at 3 o’clock behind a magnified window, and the day wheel is bilingual English / Arabic — the configuration Seiko supplied to Middle East markets. Around it runs the black unidirectional 60-minute bezel, and the screw-down crown sits at 3 rather than at the SKX007’s 4.
Inside is the calibre 7S26A, signed SEIKO TIME CORP. 7S26A — TWENTY-ONE JEWELS — JAPAN across the rotor. It is a pure automatic: 21 jewels, 21,600 vibrations per hour and roughly 41 hours of reserve, with no hand-winding and no hacking seconds — you wake it with wrist motion or a gentle shake, and the seconds hand keeps running while the crown is pulled.
The watch comes on its Seiko steel bracelet, the folding clasp stamped SEIKO, so this is the correct factory band type for the reference rather than a later replacement.
Technical Specifications
- Brand: Seiko
- Line: SKX mid-size diver-style sports (SKX021 / 023 / 025 / 027 family)
- Reference Number: 7S26-0050 — model SKX023
- Movement: Seiko calibre 7S26A, automatic, 21 jewels, 21,600 vph, approx. 41 h power reserve; no hand-winding, no hacking
- Serial Number: 382665
- Production Date: August 2003
- Case Material: Stainless steel
- Case Diameter: Approx. 37 mm (excluding crown)
- Bezel: Black unidirectional 60-minute rotating bezel
- Crown: Screw-down, at 3 o’clock
- Dial: Glossy black with applied luminous markers; day-date at 3 o’clock, bilingual English / Arabic day wheel
- Crystal: Hardlex mineral glass
- Case-back: Screw-down stainless steel with embossed Seiko wave medallion — 7S26-0050 A0 / WATER RESISTANT 10BAR / JAPAN 382665
- Bracelet: Stainless steel Seiko bracelet with signed folding clasp
- Water Resistance: 10 bar / 100 m as originally rated — a dive-styled sports watch, not an ISO-certified diver’s watch. The seals are over twenty years old, so we do not recommend any water contact.
- Country of Manufacture: Japan
Condition Report
The dial is excellent — the black finish is unmarked and the luminous plots are all present, even in colour and firmly seated. The Hardlex crystal is clear, with only fine surface scratches that catch direct light. The bezel insert is sound and its printing crisp; there is one small mark low on the left-hand side of the insert, visible in the close-up photographs.
The case has been worn and shows it honestly: light handling scratches across the polished flanks and lug tops, and a scattering of finer marks on the case-back around the wave medallion, which is still sharp and fully legible. The bracelet carries the most wear of anything here — the clasp cover is noticeably scratched from daily use and the links have dulled — but it is all cosmetic, and the clasp closes firmly. The movement is clean and the watch runs and sets correctly. The crown and case-back both screw down, but with original gaskets of this age the watch should be treated as not water-resistant.
This watch has recently been serviced by a professional watchmaker and keeps good time.
Comes complete with original steel bracelet*.
(*)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.
This watch ships from 🇺🇦 Ukraine with tracking number
Why Collectors Want This Watch Today
The mid-size 0050 answers the one complaint people consistently make about the SKX007: size. At about 37 mm this is a diver-styled Seiko that a slimmer wrist can wear without it looking borrowed, and the proportions read far more classical than the modern 42 mm-plus norm.
The calibre 7S26 is also one of the most practical automatics ever built. It was made in enormous numbers, every watchmaker knows it, and parts remain easy to source — which is precisely why these watches are still running decades after they left the factory.
There is no need to overstate the rarity: the SKX family was mass-produced and sold worldwide. What has changed is that the whole line was discontinued in 2019, so the supply is now fixed — and the mid-size references were always made in smaller numbers than the SKX007, so they simply turn up less often. The bilingual English / Arabic day wheel is a regional detail many collectors enjoy, and this is a Japanese-made, correctly signed example on its own bracelet rather than one of the modified “mods” that have absorbed a large share of surviving SKX cases.
Modes of payment:
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We guarantee the item you receive looks and works exactly as advertised — or your money back.
Seiko lug-width matched leather straps — 18 / 19 / 20 mm
About the watch factory
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 is one of the few watch companies that is fully 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 2017, Grand Seiko was spun off into its own standalone luxury brand, while Credor remains part of Seiko’s own lineup, sold primarily in Japan. Seiko’s own global lineup now includes Grand Seiko, King Seiko, Prospex, Astron, Presage, and Seiko 5 Sports.
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.
