Vintage SEIKO "Time Sonar" 7015A-6010S, ca. 1978 (from Tim)

A Flyback Chronograph! ...
I had to quickly update myself about the 7015A movement since it was still missing in my collection. I found this great article on the Seiko Citizen Watch Forum (SCWF) from Don. Since it is a great overview over 60ies and 70ies chronographs, I copied the article here (one never really knows what is happening to some posts)

Quick Setting instructions:
1) Crown in like in picture, press crown to advance the Day
2) Crown one position out, turn to advance the Date
3) Crown two positions out, turn to set the Time

And that's it in a nutshell. The watch cannot be handwound, but swaying it for ca. 30 seconds will give it a good enough initial load to keep ticking.