The Speedmaster was born in 1957 as a racing chronograph, one of a trilogy of Omega tool watches launched that year, and its founding innovation had nothing to do with space: the CK2915 moved the tachymeter scale off the dial and onto the bezel, an industry first that made the dial legible and became so standard that nobody remembers it needed inventing. The broad arrow hands gave the reference its nickname, and the caliber 321 gave it its heart.
Three years of production before the CK2998 replaced it means genuine scarcity, and the reference's status as the origin of the entire Speedmaster line has made it the vintage Omega trophy: a first-series CK2915 set the all-time auction record for the model. At that altitude the usual rules compound - every broad arrow hand, every bezel, every dial is a candidate for later substitution, and specialists exist because they are needed.
The founding file of the second brand on this site, and the same advice the 1916-D dime and the first Submariner get: at trophy level, buy the documentation, the specialist opinion and the seller before the watch. The romance is real; make sure the parts are.
Production windows and specifications compiled from documented collector references and period catalogs, cross-checked across independent sources; manufacturer records for this era are approximate by Seiko's own account.