Based on Seiko serial numbers substantiated by watches in collector hands, Seiko appear to have started production of their 6139 automatic chronograph in February ’69 and by March had produced at least 4000 watches. Seiko had thousands of watches completed when the others only had prototype watches to show along with lots of marketing hype.

The Seiko 6139 is arguably a much more technically sophisticated watch than the others also. It was the first automatic chronograph to use a vertical clutch, it used column timing control and was an integrated chronograph. The Swiss didn’t come up with a chronograph incorporating these technical features until 1987 when the F. Piguet 1185 movement was introduced.

Seiko never publicly hyped the 6139, as they were busy hyping the first quartz movement production watch, the Astron, which they introduced at Basel in 1969.