1957–19595 variants
The first Speedmaster, launched as part of a professional trio with the Seamaster 300 and Railmaster. The first chronograph with its on the rather than the dial. Steel , broad arrow hands, 19 mm lugs and 321. Designed by Claude Baillod with a team under Pierre Moinat.
One Phillips essay estimates 3,000–4,000 made. Observed movement numbers cluster around 15.49M, 15.5M, 15.99M and 16.64M.
Faded ends mark approximate or unknown dates. Years are as stated by the cited sources.
First series. Metal Base 1000 bezel, broad arrow hands, oval “O” in the signature and “Speedmaster” engraved on the caseback bevel. Some bezels have a flat-topped “3”, thought to be very early. Example: movement 15,500,198, made January 1958.
Second series, essentially identical to the -1: Base 1000 metal bezel, broad arrow hands, “fat” oval O and bevel-engraved caseback. Archive-dated examples 1958–January 1959, movement numbers 15.50M and 15.99M.
Third series, seen with either broad arrow or alpha hands and with either the steel bezel or a black Base 1000 bezel; no pattern between the two is proven. “Speedmaster” moves from the bevel to the back, nearer the seahorse. Observed movement numbers around 16.64M.
Specs shared by all variants. Variant pages show where a variant differs.