Seiko watch 7015-6010 Time Sonar flyback Chronograph

THE WATCH

The name comes from the semi transparent round dial that reminds us of a sonar screen.

Seiko’s automatic 701x series – including this serviced, 1970s Seiko 7015-6010 Time Sonar chronograph here – arrived to the market two years later than Seiko’s famed 6139 series, with both featuring a similar single-register 30-minute layout and day/date complication. However, the two movements shared no components, and the 701x had its own rather unique feature - certain models, like the one here, were signed “Time-Sonar” on the dial and were the first automatic chronographs available with display backs, a rarity for any watch at the time. Although similar to the 6139 series, the 701x series was arguably the more technically advanced of the chronograph movements.  The 7015 has an additional flyback functionality (which allows the user to immediately restart the chronograph without having to first stop and reset, akin to the popular vintage Citizen 8110 bullhead). 

Of note, the 701x series was the thinnest vertical clutch column wheel chronograph during a portion of the 1970’s, existing from 1970 through ’77.  The movement has a diameter of approximately 27mm and is only an astounding 6.4mm tall, which is significantly thinner than the 6139.  Finally, the 701x line had some of the most attractive variations of any early Seiko chronographs, including the square cased 7016-5001 “Seiko Monaco.”

OUR THOUGHTS

The vintage Seiko Time Sonar 7015-6010 is one of the most unique watches we have had the pleasure of working on. It’s absolutely different from anything Seiko was making at the time and they’ve never done anything quite like it since, until the reissue in 2021. This Time Sonar is a must have for any collector, especially in this condition with the display case back as good as this one, as they are often found cracked or heavily worn.