Update: 50th Anniversary of the first automatic chronograph - Seiko’s 6139

I have updated the article about the first release of the 6139 chronograph to include an article from the Suwa Seiko internal company newsletter. This article supports the May 1969 market introduction date of the models.

The revised article on the release of the Seiko 6139 chronographs can be found here:
50th Anniversary of the first automatic chronograph - Seiko’s 6139