Seiko Calculator Chronograph 6138-7000
Record status
Individual type · partial
Period
1971
Maker / issuer
SeikoThis Seiko Calculator Chronograph, reference 6138-7000, dates to 1971. The watch features a 45 mm stainless steel case and is notable for its integrated slide rule bezel, which includes a secondary transparent plastic indicator for mathematical calculations.
The dial is matte black with metallic grey sub-registers, accented by orange chronograph hands and ivory-toned luminous markers. Powering the watch is the automatic Seiko caliber 6138, the brand's first dual-register chronograph movement. It is fitted with an original Seiko steel bracelet. The watch has been recently serviced according to the source. It is presented without original documentation or packaging. The case has undergone a light polish while retaining its original dimensions.
The slide rule bezel remains in black with minor signs of wear. The crown, push-pieces, and case back are present.
Evidence at a glance
- Linked sources
- 1
- Photograph views
- 1
- Catalogue references
- 0
Counts describe this entry’s documentation, not authenticity, rarity or completeness. Photographs may show one specimen; check each caption and licence.
Technical characteristics
- Date
- 1971
- Type
- Chronograph
- Maker
- Seiko
- Model
- Calculator Chronograph
- Bracelet
- Original Seiko steel
- Movement
- Seiko Cal. 6138
- Reference
- 6138-7000
- Case Diameter
- 45 mm
- Case Material
- Stainless steel
- Place recorded
- Japan
- Maker / attribution
- Seiko
Design
- Design and Dial
- The watch features a 45 mm stainless steel case, which the source reports has undergone a light polish but maintains its original angles and proportions. The matte black dial is configured with two metallic grey sub-registers and ivory-colored luminous markers. Orange hands are utilized for the chronograph functions, providing visual coordination with the orange markings on the slide rule bezel. A distinctive feature of this model is the functional slide rule bezel in black, equipped with a secondary transparent plastic indicator. This mechanism is designed to facilitate mathematical calculations. The watch includes a day and date display aperture on the dial.
- Visible features
- • Slide rule bezel with secondary transparent plastic indicator • Matte black dial with metallic grey sub-registers • Orange chronograph hands • Seiko automatic Caliber 6138 movement
- Bracelet and Condition
- The watch is provided on an original Seiko steel bracelet. According to the source, the bracelet exhibits slight stretching and is sized to accommodate a wrist circumference of up to 7 and 3/4 inches. The push-pieces, crown, and case back, which features factory engravings, are reported to be in satisfactory condition. The described condition represents the current state as reported by the selling entity.
- Movement and Technical Specifications
- Internally, the watch is driven by the Seiko caliber 6138 automatic movement. This caliber, which succeeded the 6139, is identified as the brand's first dual-register chronograph movement. The configuration allows for a comprehensive chronograph display in an automatic format. The watch includes a day and date complication integrated into the dial. The source states that the movement has been recently serviced and provides accurate timekeeping performance.
Identification
- Reference
- 6138-7000
- Source note
- Facts transcribed from the linked source listing or collection record. Attribution and specifications are source-reported and have not been independently authenticated.
Catalogue references
No catalogue numbers recorded. Numbers are only published once transcribed from a verified edition of a standard catalogue — they are never inferred.
Research required
- Research required: The exact state of the movement's long-term accuracy is not verified by this site
- Research required: The authenticity of individual internal components is not independently confirmed