One of the most fascinating aspects of the rivalry between Seiko’s Suwa and Daini divisions was their battle for chronograph supremacy. While vintage enthusiasts often focus on Suwa’s iconic 613X chronographs, Daini’s response with the 701X series was equally impressive, and in some ways, ahead of its time.
 
A standout from this era is Daini's Time Sonar Ref. 7015-6010 which was introduced in 1976. Inspired by submarine sonar displays, it features a distinctive transparent dial that reveals the calendar disk beneath.
 
In our opinion, the Time Sonar perfectly captures the futuristic design of the 1970s as interpreted by Japanese watchmaking: Its translucent dial showcases the quick-set calendar mechanism, making it a truly unique piece in the world of vintage chronographs. Adding to its allure is the 'smoked' display case back, offering a glimpse of its iconic Cal.7015A making it one of the first mass-produced wristwatches to feature such a display.
 
If you’re seeking this reference, this immaculate, unused example we're offering is a rare find in today’s market. While Seiko has revisited the design in the Kosuke Kawamura series SRPJ41 & SRPJ43 in 2022, nothing compares to the allure of the original.
 
The watch currently works flawlessly and will be sold as-is. Please let us know if you wish to service it.
 
Ships from Tokyo, Japan.