Chronomaster

Chronomaster is Zenith's family of mechanical chronographs, watches that combine ordinary timekeeping with a stopwatch. The collection began in 1994. Its best-known movement, the El Primero, is older: Zenith introduced it in 1969.

The early El Primero combined automatic winding with a high-frequency chronograph. Its balance made ten half-swings each second, allowing the stopwatch to divide a second into tenths. The 1969 A386 housed it in a round 38 mm steel case with three overlapping counters in different colors.

That watch became an important reference point for later designs. The steel A386 Revival included in Zenith's 2019 anniversary set returned to its size and layout, using caliber 400. The familiar colors helped separate running seconds from elapsed minutes and hours.

The later Chronomaster Original looks closely related but changes the reading. Its caliber 3600 sends the central stopwatch hand around the face once in ten seconds, instead of once in a minute. The tenths become much easier to spread out around the circumference.

The distinction is visible when the chronograph runs, not simply when the watches are placed side by side. Similar-looking dials can ask the reader to follow time at very different speeds.