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The Encyclopedia of Horology

Wristwatch · Chronograph

Seiko Sports Speed-Timer 'Bullshead' Chronograph Wristwatch

Partially verified

A gentleman's Seiko Sports Speed-Timer 'Bullshead' automatic chronograph wristwatch, reference 6138 with serial number 571434. The 44mm stainless steel case features an external tachymeter bezel surrounding a brown dial with twin light-toned registers. Positioned in a bullhead layout, the winding crown and chronograph pushers sit along the 12 o'clock case flank. The dial displays a vertical day-date window at 6 o'clock. According to the source, the watch is powered by a signed automatic calibre 6138B and fitted with a signed stainless steel bracelet featuring a folding clasp.

Front view of the Seiko Sports Speed-Timer 'Bullshead' chronograph wristwatch on steel bracelet
Front view of the Seiko Sports Speed-Timer 'Bullshead' chronograph wristwatch on steel bracelet — Fellows. Rights pending — permission not yet requested. Original source

Catalogue identity

Source
www.fellows.co.uk
Category
Wristwatch · Chronograph
Maker / attribution
Seiko
Reference
6138
Catalogue / lot identifier
205
Source-reported date
Not established
Source-reported place
Japan
Source-reported serial
571434

Source-reported attribution and specifications are not independent authentication. A listing does not establish present ownership, current display, availability or permission to reproduce.

Object description

Watch Identity and Configuration

This is a gentleman's Seiko Sports Speed-Timer 'Bullshead' chronograph wristwatch. The watch is constructed with a stainless steel case and features a tachymeter bezel. It is identified by reference 6138 and serial number 571434.

The watch features a 'bullhead' orientation, where the chronograph pushers and winding crown are positioned on the 12 o'clock flank of the case. It is powered by a signed automatic calibre 6138B and includes a brown dial, with the watch fitted to a signed stainless steel bracelet with a folding clasp.

Evidence for this section
  • “SEIKO - a gentleman's Sports Speed-Timer 'Bullshead' chronograph bracelet watch.”
  • “Stainless steel case with tachymeter bezel.”
  • “Reference 6138, serial 571434.”
  • “Signed automatic calibre 6138B.”
  • “Chronograph pushers and winding crown are positioned at the 12 o'clock flank of the case in a bullhead orientation.”

Condition and Observations

The source reports that the movement is not currently functioning and exhibits scratches, marks, and tarnishing. The bracelet is approximately 19cm in length including the case and shows signs of stretching to the links, while the clasp remains functional despite visible marks.

The dial displays noticeable marks and scratches, and the glass has noticeable scratches and marks. The case shows noticeable scratches, marks, and dints.

Evidence for this section
  • “Movement is not currently functioning.”
  • “Movement has scratches, marks and tarnishing commensurate with general wear visible to the naked eye.”
  • “Dial appears to have noticeable marks and scratches.”
  • “Glass has noticeable scratches and marks.”
  • “Case shows noticeable scratches, marks and dints.”
  • “Bracelet measures approximately 19cm including case.”

Alterations and Documentation

Several components have been identified as altered or replaced. The hands have been repainted and exhibit tarnishing and marks. The crown is a non-original smaller replacement showing scratches and marks.

The lot does not include a box or papers. Fellows does not guarantee the working order or accuracy of the lot.

Evidence for this section
  • “Hands show noticeable marks and tarnishing. Hands have been repainted.”
  • “The crown is not original and is a smaller replacement.”
  • “This lot does not come with box or papers.”
  • “Fellows do not guarantee the working order or accuracy of any lots sold.”

Open research questions

  • What specific maintenance or parts are required to restore the non-functioning calibre 6138B movement?
  • Are there diagnostic methods available to confirm if other internal components are original to the 6138 reference?

Source evidence

Recorded claims and source quotations for Seiko Sports Speed-Timer 'Bullshead' Chronograph Wristwatch
FieldSource-reported valueSource quotation
Reference6138“Reference 6138, serial 571434.”
Serial number571434“Reference 6138, serial 571434.”
Calibre6138B“Signed automatic calibre 6138B.”
Dial colourBrown“Brown dial.”

Visible details

  • Chronograph pushers and winding crown are positioned at the 12 o'clock flank of the case in a bullhead orientation.
  • Brown dial with two cream-coloured sub-dials situated at 9 and 3 o'clock.
  • Vertical day and date display at 6 o'clock displaying a Kanji day character.
  • Brown tachymeter bezel ring displaying noticeable surface wear, marks, and loss along the outer edges.

Research qualifications

  • Source notes the movement is not currently functioning.
  • The crown is reported as a non-original smaller replacement.
  • Hands show visible marks, tarnishing, and have been repainted.
  • Dial, crystal, and case exhibit noticeable scratches, marks, and dints.
  • No box or documentation are included.

Photograph identity and source facts were screened before import; rights clearance remains pending.

Consulted source

Lot 205 | SEIKO - a gentleman's stainless steel Sports

Reviewed 2026-10-22 · Record 1276b6c296

Terms in this record

Glossary explanations for terms named in this object’s record.

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