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Seiko SpeedTimer Chronograph (Ref. 6138-0040) "Bullhead", 1976 — view 1 of 6
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Wristwatches · Wristwatch

Seiko SpeedTimer Chronograph (Ref. 6138-0040) "Bullhead", 1976

DocumentedDocumented from a dealer's listing; attribution and date as stated by the dealer.
Maker / attribution
Seiko (maker)
Date
1976
Country of origin
Japan
Object type
Wristwatch
Stock no.
SKOSTCH61380040
Credit line
Dealer listing, Craft & Tailored (SKOSTCH61380040)
Catalogue title (original)
1976 Seiko SpeedTimer Chronograph (Ref. 6138-0040) "Bullhead" (English)

View the source record (dealer listing) ↗ (opens another website in a new tab)Suggest a correction

Record summary

Catalogued by Craft & Tailored (dealer), Los Angeles (stock number SKOSTCH61380040), this is a wristwatch by Seiko, made in Japan, dated 1976. The Atlas places it in the Quartz Revolution period (1969 – 1990) of its Wristwatches collection. The record is illustrated with 6 photographs.

Assembled from the source record's structured fields. Dates and attributions are given as the source states them; where a field is missing the Atlas leaves it blank rather than estimating.

Catalogue description

Dealer description — Craft & Tailored

This is the classic 6138-0049 Seiko Bullhead chronograph. Seiko started producing this timepiece in 1975 and concluded the production in 1978. The 6138 line of Seiko's are highly collectible for two reasons; the Seiko designed 6138B movement is very precise and highly accurate, and they are a blast back into the iconic design trends of the 1970s. The name Bullhead comes from the unique ergonomic shape of the case that features an asymmetrical thickness, being thicker at the top and slimmer at the bottom. Rather than having the crown and chronograph pushers on the right side of the case, like traditional chronographs, the movement has been rotated so the crown and pushers are at the top of the case, at the 12 o'clock position, giving the chronograph pushers a resemblance to the horns of a bull. The theory behind this unique design is you’re less likely to engage or disengage the chronograph with the pushers at the top, as opposed to the side. The design of the Seiko Bullhead was built around the active sporting lifestyle. The Seiko Bullhead came in two dial variants; a copper dial with gold subdials and a black dial with light blue subdials. Brown bullheads also come in additional SpeedTimer variants. SpeedTimer Bullhead variants were produced for the Japanese Domestic Market and were sold exclusively in Japan and surrounding areas. The Bullheads produced for the rest of the world wore the standard "Chronograph Automatic" markings. Stock # SKOSTCH61380040 Brand Seiko Style SpeedTimer "Bullhead" Chronograph Model 6138-0040 Serial 65XXXX Size Men's Material Stainless Steel Dial Brown "Ombre" Millimeters 43.5 Bracelet 2pc Handmade Leather Strap CASE & BRACELET The unpolished asymmetrical case is exceptional, retaining strong factory brushing and crisp lines with light signs of use. The amber tachymeter bezel is in excellent condition showing almost no signs of use and no fading. The bullhead crown and pushers are original to the watch. The case back retains all of its factory engravings in crisp and deep condition. The watch will come supplied on a 2pc handmade leather strap. DIAL & HANDS The brown "ombre" dial is lighter in the center and gradually becomes darker towards the minute track, and features a metallic gold window around the date and sub-dials. The non-luminous dial is in flawless original condition, showing no signs of age or damage. The original hands are in flawless original condition as well. ACCESSORIES None. The watch is keeping time and functioning perfectly, previous service history is unknown.

Historical context

Quartz Revolution (1969 – 1990)

Seiko's Astron begins mass quartz timekeeping; traditional industries contract sharply.

Quartz and digital watches transformed the market after 1969. Swiss employment collapsed, Japanese and Hong Kong production soared, and the Swatch (1983) helped the Swiss industry recover; mechanical watches survived as luxury goods.

Read the period in the timelineMore wristwatches from this periodEarlier: Modern Mechanical Horology

Atlas type guide

Chronographs and split-seconds watches

A chronograph is a watch with an additional seconds hand that can be started, stopped and returned to zero independently of the timekeeping. Louis Moinet built an early example in 1816 and Nicolas Rieussec a recording 'chronographe' in 1821; Adolphe Nicole's heart-shaped reset cam (patented 1862) made the modern return-to-zero possible. Split-seconds (rattrapante) chronographs add a second hand that can be stopped for intermediate times; flyback chronographs restart instantly.

Chronographs were essential tools for doctors (pulsometer scales), artillery (telemeter), engineers and sport. In wristwatches, Valjoux, Venus, Lemania and later the automatic chronographs of 1969 (Zenith El Primero, the Chronomatic Calibre 11 group and Seiko 6139) are milestones.

What to look for

  • Push-pieces on the case band or a single button in the crown (monopusher).
  • Subsidiary registers for minutes and hours; tachymeter, telemeter or pulsometer scales.
  • Column wheel versus cam control visible in the movement.
  • Calibre markings of specialist makers (Valjoux, Lemania, Venus, Landeron).

Dating clues

  • Pocket chronographs with heart cam reset: after 1862.
  • Wrist chronographs: from c. 1910; two-button designs from the 1930s.
  • Automatic chronographs: from 1969.

General guidance written by the Atlas editors about this kind of object. It is not a statement about this particular piece; for that, rely on the source record above and on physical examination.

Read next:Flyback chronographChronograph

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