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1Repair Windows errors before they cause bigger problems2Scan for outdated or missing drivers - takes under a minute3Clear out junk files and repair common Windows errorsThe Seiko Time Sonar 7015-6010 is a mid-1970s automatic chronograph distinguished by a green semi-transparent dial and a screw-in display caseback: in the described configuration, you can see parts of its movement from both sides. Its reported caliber 7015A adds a flyback chronograph and quickset day and date. Those unusual design and mechanical details make it an intriguing vintage Seiko, but each surviving example needs to be assessed on its own condition and service history.
What is the Seiko Time Sonar 7015-6010?
The 7015-6010 is a Seiko Time Sonar automatic chronograph that Fratello places in the mid-1970s. A vintage dealer archive also identifies the reference as a 1970s automatic chronograph. Seiko’s official heritage chronology provides broader context—it records an automatic chronograph in 1969, a digital quartz chronograph in 1975, and an analog quartz chronograph in 1977—but does not name this reference or establish its specifications. Fratello’s model feature; DC Vintage Watches’ archive listing; Seiko’s heritage chronology.
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Why does the Time Sonar look different?
The defining feature is a green semi-transparent dial that reveals some of the movement beneath it. A screw-in exhibition caseback offers another view, making the watch’s mechanical character part of its appearance rather than something hidden entirely inside the case. The dealer archive also calls out the exhibition back and flyback capability. The available sources do not establish that this was Seiko’s first display-back watch, so that superlative should not be assumed.
Fratello describes a stainless-steel case with a flat mineral-glass crystal. The dial and caseback are the most distinctive elements; the remaining reported dimensions give a sense of its proportions without guaranteeing how any individual example will wear.
#1 Best Overall
- SCRATCH-RESISTANT: It features black dial orange two-tone (silver-tone and gold-tone) hand markings of a hardlex window display
- PREMIUM BRACELET: The band is made of two-tone (silver-tone and gold-tone) stainless steel and includes a fold over with safety release clasp to keep your watch secure
- CLASSIC AND SOPHISTICATED DESIGN: The silver-tone and gold-tone hands and silver-tone and gold-tone hour markers is easy to read. This timepiece is the perfect accessory for any occasion
- MOVEMENT: Constructed with high-quality materials and precise quartz movement. You can feel confident that you will receive a long-lasting, high-quality timepiece that will keep accurate time
- DURABLE PRODUCT: The stainless steel watch case is scratch-resistant, and the hardlex is highly durable. The movement is also stable and keeps time well
Reported specifications
The figures below are reported in Fratello’s description of its example, not independent measurements of every 7015-6010. Vintage watches may have been repaired, altered, or fitted with replacement parts.
| Detail | Reported specification |
|---|---|
| Model and reference | Seiko Time Sonar, 7015-6010 |
| Production period | Mid-1970s, according to Fratello |
| Case material | Stainless steel |
| Case diameter | 39 mm |
| Lug-to-lug | 42 mm |
| Thickness | 12 mm |
| Lug width | 19 mm |
| Crystal and caseback | Flat mineral glass; screw-in display back |
| Dial | Green, semi-transparent |
| Movement | Seiko caliber 7015A, automatic chronograph |
| Frequency | 21,600 vibrations per hour |
| Chronograph | One-minute chronograph with flyback, as listed by Fratello |
| Calendar | Quickset day and date |
| Hand-winding | Fratello says the movement is not hand-windable |
Fratello’s feature contains the model-specific specification list; the vintage dealer archive corroborates the reference and broad model identity, not every technical detail.
What the 7015A movement offers
Fratello describes the 7015A as an automatic chronograph movement with flyback, quickset day and date, and a rate of 21,600 vibrations per hour. The flyback function is a chronograph feature: it allows a running timing sequence to be reset and restarted with one action rather than stopping, resetting, and starting in separate steps. The article lists the chronograph as one-minute and says the movement cannot be wound by hand.
The dealer archive compares the wider 701x family with Seiko’s 6139 and claims the movements share no components. That is a dealer-authored historical claim, not an official technical specification; the more securely supported point for a 7015-6010 buyer is to verify the actual movement and its functions in the specific watch.
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Fratello characterizes the reference as relatively hard to find and says its movements can be tricky to service. These are collector observations, not a condition report for a particular watch or a guarantee that every watchmaker will encounter the same issue. Condition, originality, and service history can differ substantially from one surviving example to another.
- Reference and movement: Ask for clear photographs and, where possible, confirmation that the watch is a 7015-6010 with the expected 7015A movement.
- Dial, hands, and caseback: Inspect the semi-transparent dial and hands for damage or signs of replacement, and confirm the display back is present and correctly fitted.
- Chronograph: Have the start, stop, reset, and flyback operation checked by a knowledgeable seller or watchmaker.
- Calendar: Confirm day and date changes and ask how the quickset works on that specific watch.
- Service documentation: Request dated records and details of the work performed. If there is no service history, do not assume the watch is ready for regular use.
- Fit and strap: The reported lug width is 19 mm, but check the particular watch before buying a replacement strap.
These are practical checks based on the reported design and functions, not a manufacturer’s service checklist. Have a watchmaker assess the movement if its operation or condition is uncertain.
How to think about price and availability
Fratello reports that values vary widely and gives an example of prices approaching $1,000 in the context of its article. That historical observation is not a current valuation or a reliable price for a watch offered today. No present-day market price or current inventory is established here. Compare the exact listing’s condition, originality, documented service, and verified operation rather than treating the reference alone as a price guarantee.
For another vintage chronograph, useful points of comparison include functions—especially flyback—case dimensions, dial and caseback design, originality, service documentation, and the price of the individual example. The available sources do not support a categorical ranking of this watch against other references.
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Product prices and availability are accurate as of the date/time indicated and are subject to change. Any price and availability information displayed on Amazon at the time of purchase will apply.
