The Zenith El Primero automatic chronograph movement is a worthy contender for the pantheon of the most important mechanical calibres ever manufactured.With a high beat rate, quickset date mechanism, and full-body winding rotor, these movements are robust, reliable, and accurate — and have powered everything from the iconic A386 chronograph to the Rolex Daytona, plus a bevy of lesser-known models from brands such as Movado and Waldan. In the 1990s, Zenith released a fresh line of chronograph models incorporating the El Primero movement which it called the Rainbow. Named after the victorious sailboat in the 15th America’s Cup in 1934, certain versions of these watches were indeed as colorful as their namesake, while others were subdued and monochromatic. The watch we have here is an example of the latter.Housed in a 40mm stainless steel case, it features a gloss-black tritium dial with applied indices, radial subsidiary registers, a matching ‘sword’ handset, and a date window at 4:30. Also featuring a sapphire crystal, a signed crown, screw-down pushers, and a fixed, stainless steel tachymeter bezel. It comes paired to a stainless steel multi-link bracelet with a signed folding clasp, and includes its inner and outer boxes and books.Powering this Reference 15/02-0460-400 is, of course, an automatic El Primero calibre from Zenith — the famed chronograph movement that saw the maison through the end of the Quartz Crisis when Rolex came knocking at Zenith’s door. This watch is an excellent reminder of the horological creativity of the 1990s, a time that collectors often overlook……to their detriment, in our opinion!